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Keep the circulating pump running for 2-3 mins after boiler shuts off

124

Comments

  • #92
    jimf
    Registered Users, Registered Users 2 Posts: 4,052 ✭✭✭jimf


    don't do plumbing john so cant comment on best practice


    but what I do know I think

    the bypass should be fitted after the pump and before any motorised valves


    if the frost stat is activated and the boiler is called to heat the water then should circulate through the bypass allowing a circuit back to the boiler thus
    allowing the boiler stat to work with its usual function

    the frost stat should without doubt activate the pump if wired correctly

    can be either manual or automatic


  • #93
    Wearb
    Moderators, Home & Garden Moderators Posts: 6,707 Mod ✭✭✭✭Wearb


    jimf wrote: »
    don't do plumbing john so cant comment on best practice


    but what I do know I think

    the bypass should be fitted after the pump and before any motorised valves


    if the frost stat is activated and the boiler is called to heat the water then should circulate through the bypass allowing a circuit back to the boiler thus
    allowing the boiler stat to work with its usual function

    the frost stat should without doubt activate the pump if wired correctly

    can be either manual or automatic
    Best practice in that situation would be a pipe stat to knock of the frost stat call for heat before the boiler stat does it, thereby saving a few bob on fuel.



    Ok! Time a late one or two :pac::pac::pac:


  • #94
    jimf
    Registered Users, Registered Users 2 Posts: 4,052 ✭✭✭jimf


    Wearb wrote: »
    Best practice in that situation would be a pipe stat to knock of the frost stat call for heat before the boiler stat does it, thereby saving a few bob on fuel.



    Ok! Time a late one or two :pac::pac::pac:


    us limerick boys love wasting money :D

    enjoy the few pints great for some out on a Thursday :rolleyes::rolleyes:

    jaysus more wires to totally over complicate it


  • #95
    agusta
    Closed Accounts Posts: 1,590 ✭✭✭agusta


    jimf wrote: »
    don't do plumbing john so cant comment on best practice


    but what I do know I think

    the bypass should be fitted after the pump and before any motorised valves


    if the frost stat is activated and the boiler is called to heat the water then should circulate through the bypass allowing a circuit back to the boiler thus
    allowing the boiler stat to work with its usual function

    the frost stat should without doubt activate the pump if wired correctly

    can be either manual or automatic
    correct


  • #96
    jimf
    Registered Users, Registered Users 2 Posts: 4,052 ✭✭✭jimf


    agusta wrote: »
    correct

    ah jaysus what you stuck for

    you agree with me


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  • #97
    John.G
    Registered Users, Registered Users 2 Posts: 3,916 ✭✭✭John.G


    agusta wrote: »
    correct

    And the by-pass is a spring loaded valve adjusted to open only when all zone valves are closed to avoid re circulation when not needed?.


  • #98
    agusta
    Closed Accounts Posts: 1,590 ✭✭✭agusta


    Everyone deserves a compliment now and again. i know your feeling a little down over the new boiler you lost over the asbestos flue:eek:,.so a compliment is nice


  • #99
    agusta
    Closed Accounts Posts: 1,590 ✭✭✭agusta


    agusta wrote: »
    Everyone deserves a compliment now and again. i know your feeling a little down over the new boiler you lost over the asbestos flue:eek:,.so a compliment is nice
    For Jimf


  • #100
    jimf
    Registered Users, Registered Users 2 Posts: 4,052 ✭✭✭jimf


    agusta wrote: »
    For Jimf


    it was probably the best thing that ever happened

    now I dont ever have to go back shes all yours again


  • #101
    jimf
    Registered Users, Registered Users 2 Posts: 4,052 ✭✭✭jimf


    John.G wrote: »
    And the by-pass is a spring loaded valve adjusted to open only when all zone valves are closed to avoid re circulation when not needed?.

    probably best to have automatic


    as I could imagine a manual being left too open and robbing water needed for the heating etc


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  • #102
    agusta
    Closed Accounts Posts: 1,590 ✭✭✭agusta


    John.G wrote: »
    And the by-pass is a spring loaded valve adjusted to open only when all zone valves are closed to avoid re circulation when not needed?.[/QUOTEYes, Without knowing fully how the spring works,id say yes. the extra pressure in the circuit will open the automatic by pass allowing flow back to the boiler,also protecting the circulating pump. It can also open when a zone valve is open but thermostatic rad valves are satisfied,[closed] thus also closing the circuit


  • #103
    John.G
    Registered Users, Registered Users 2 Posts: 3,916 ✭✭✭John.G


    agusta wrote: »
    John.G wrote: »
    And the by-pass is a spring loaded valve adjusted to open only when all zone valves are closed to avoid re circulation when not needed?.[/QUOTEYes, Without knowing fully how the spring works,id say yes. the extra pressure in the circuit will open the automatic by pass allowing flow back to the boiler,also protecting the circulating pump. It can also open when a zone valve is open but thermostatic rad valves are satisfied,[closed] thus also closing the circuit

    I read somewhere that some come set at 0.2 Bar (2M) but are adjustable up to 0.6 Bar (6M), it will be interesting to see what results the OP's test shows tomorrow and see if its actually recirculating, if its been set up correctly and with his stated pump speed setting of 3 then it should be, if not then no circulation leading to possible hi limit stat tripping if frost stat in operation.


  • #104
    John.G
    Registered Users, Registered Users 2 Posts: 3,916 ✭✭✭John.G


    Wearb wrote: »
    Best practice in that situation would be a pipe stat to knock of the frost stat call for heat before the boiler stat does it, thereby saving a few bob on fuel.



    Ok! Time a late one or two :pac::pac::pac:

    I just read there that sometimes a pipe stat is attached to the return wired normally closed (NC) and set to open at 30/35C to cut out the frost stat.


  • #105
    jimf
    Registered Users, Registered Users 2 Posts: 4,052 ✭✭✭jimf


    John.G wrote: »
    I just read there that sometimes a pipe stat is attached to the return wired normally closed (NC) and set to open at 30/35C to cut out the frost stat.


    I wonder is this really needed as the bypass will be so close to the boiler savings would be minimal

    if this was to fail when in the operational mode you would then have no frost protection

    with such a low volume of water being heated time would be minutes I think

    how often will the frost stat operate anyway


  • #106
    John.G
    Registered Users, Registered Users 2 Posts: 3,916 ✭✭✭John.G


    jimf wrote: »
    I wonder is this really needed as the bypass will be so close to the boiler savings would be minimal

    if this was to fail when in the operational mode you would then have no frost protection

    with such a low volume of water being heated time would be minutes I think

    how often will the frost stat operate anyway

    Savings probably minimal all right, I would be quite happy with just the frost stat or even just the pipe stat alone attached to the boiler return and set to operate at say 6C, if it has a wide hysteresis of say 15C then it will achieve the object of keeping the water from freezing with minimal burner firing?.

    I wonder is there anything in the the building regulations regarding this.


  • #107
    Wearb
    Moderators, Home & Garden Moderators Posts: 6,707 Mod ✭✭✭✭Wearb


    John.G wrote: »
    Savings probably minimal all right, I would be quite happy with just the frost stat or even just the pipe stat alone attached to the boiler return and set to operate at say 6C, if it has a wide hysteresis of say 15C then it will achieve the object of keeping the water from freezing with minimal burner firing?.

    I wonder is there anything in the the building regulations regarding this.
    I would have to agree with you and Jim in this instance.

    Here is what was in my mind when I replied.


    "Where the frost thermostat is installed outside the house (to protect
    a boiler installed in an external boiler room or garage) or in an
    attic, it is recommended that it be used in conjunction with a pipe
    thermostat to avoid unnecessary and wasteful overheating of the
    property. The pipe thermostat should be located on the boiler return
    pipe, and set to operate at 30°C."


  • #108
    John.G
    Registered Users, Registered Users 2 Posts: 3,916 ✭✭✭John.G


    Wearb wrote: »
    I would have to agree with you and Jim in this instance.

    Here is what was in my mind when I replied.


    "Where the frost thermostat is installed outside the house (to protect
    a boiler installed in an external boiler room or garage) or in an
    attic, it is recommended that it be used in conjunction with a pipe
    thermostat to avoid unnecessary and wasteful overheating of the
    property. The pipe thermostat should be located on the boiler return
    pipe, and set to operate at 30°C."

    Doing a bit of thinking again about this,

    I suppose one would have to admit that where there is no zoning installed (still common enough in systems fitted with TRV's like my own) then "whole house" heating will occur from the time the frost stat operates to the time it cuts out which may be a very long time depending on boiler house+boiler+pipework insulation quality. The pipe stat will shutdown the boiler as soon as the return temperature reaches 25C/30C or whatever.

    But again, as stated above, how often does the frost stat operate/annum and "whole house" heating isn't a complete waste.


  • #109
    John.G
    Registered Users, Registered Users 2 Posts: 3,916 ✭✭✭John.G


    Wearb wrote: »
    I would have to agree with you and Jim in this instance.

    Here is what was in my mind when I replied.


    "Where the frost thermostat is installed outside the house (to protect
    a boiler installed in an external boiler room or garage) or in an
    attic, it is recommended that it be used in conjunction with a pipe
    thermostat to avoid unnecessary and wasteful overheating of the
    property. The pipe thermostat should be located on the boiler return
    pipe, and set to operate at 30°C."

    There's a interesting thread here (only a year or so old) re frost protection with drawing included.
    https://www.boards.ie/vbulletin/showthread.php?t=2057714946


  • #110
    Shower Doctor
    Banned (with Prison Access) Posts: 36 ✭Shower Doctor


    Wearb wrote: »
    I would have to agree with you and Jim in this instance.

    Here is what was in my mind when I replied.


    "Where the frost thermostat is installed outside the house (to protect
    a boiler installed in an external boiler room or garage) or in an
    attic, it is recommended that it be used in conjunction with a pipe
    thermostat to avoid unnecessary and wasteful overheating of the
    property. The pipe thermostat should be located on the boiler return
    pipe, and set to operate at 30°C."

    Who recommends it?


  • #111
    whizbang
    Registered Users, Registered Users 2 Posts: 2,076 ✭✭✭whizbang


    Post #23, Picture 1.

    With Trv's and Zones closing, the pump could be sucking air through the leaking coupler on inlet side of pump.
    AAV is doing its job for the next run, (hinted by the water marks..)

    3 NRV's ???


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  • #112
    Blowheads
    Registered Users, Registered Users 2 Posts: 437 ✭✭Blowheads


    whizbang wrote: »
    Post #23, Picture 1.

    With Trv's and Zones closing, the pump could be sucking air through the leaking coupler on inlet side of pump.
    AAV is doing its job for the next run, (hinted by the water marks..)

    3 NRV's ???

    Sorry, could you explain this in lay man's terms?


  • #113
    John.G
    Registered Users, Registered Users 2 Posts: 3,916 ✭✭✭John.G


    Blowheads wrote: »
    Sorry, could you explain this in lay man's terms?

    He may be referring to the signs of leakage on the suction side of the pump (RH side of pump if you turn picture 90 deg clockwise) and also the boiler flow side piping where there appears to be a number of fittings and is asking are they (3) NR valves and what is their purpose, There appears to be a AAV (automatic vent valve) like a T piece on the flow side at the top of the boiler.


  • #114
    corkgsxr
    Registered Users, Registered Users 2 Posts: 3,388 ✭✭✭corkgsxr


    Jumping in late here

    I'd check are those non returns actually moving.

    I'd be suspicious of that pump. It's in the wrong orientation and weren't the best pumps anyway.


  • #115
    Blowheads
    Registered Users, Registered Users 2 Posts: 437 ✭✭Blowheads


    corkgsxr wrote: »
    Jumping in late here

    I'd check are those non returns actually moving.

    I'd be suspicious of that pump. It's in the wrong orientation and weren't the best pumps anyway.

    Should I change out all that plumbing on the right? Take it those nrt?

    When you mean pump orientation? What change the pump to a? And what way to orient it?


  • #116
    John.G
    Registered Users, Registered Users 2 Posts: 3,916 ✭✭✭John.G


    Because you have two systems linked together, an oil fired system and solid fuel, then if one only is in service you don,t want the water from one system to circulate through the other's boiler, for example if you had the solid fuel system in service only, then in your case you don,t want the water to circulate through the oil fired boiler, there are various means of achieving this, some more complex than others, in your case it would seem that it is achieved by having a non return (NR) valve fitted in the flow line from the oil boiler, there should similarly be another NR valve fitted in the flow line from the solid fuel boiler. Only one NR valve is required in either system and the question that is being posed is why are there apparently three fitted in the oil fired boiler. The first thing is to establish if in fact these are NR valves (and ask your plumber what does he think, maybe he actually installed it). IMO the correct type of NR valve for this application is a swing check type because it offers the least resistance to flow. IF there are in fact 3 of the spring loaded type NR valves fitted in your system then they will offer a big resistance to flow, you have a 5M pump running at its maximum speed setting (3) possibly to overcome this resistance.
    I can't define the posters meaning of orientation. The circ pumps are either fitted in the flow from the boiler or in the return before the boiler, again IMO both positions have pros and cons, in your case the circ pump is fitted in the return before the oil fired boiler ( you can check the solid fuel system to see where it's circ pump is fitted), the important think is that the flow direction is upwards through the boiler(s), you have already proved that the flow is in the correct direction in the oil fired boiler.

    Actually in the case of the oil fired boiler above, it has to be the spring loaded type of NR valve that is fitted because if a swing check was installed the valve clack would be hanging down and would remain fully open so of no use in this position.


  • #117
    Wearb
    Moderators, Home & Garden Moderators Posts: 6,707 Mod ✭✭✭✭Wearb


    The shaft of the pump must be horizontal, which in this case it seems to be, but the photo might be confusing.


  • #118
    John.G
    Registered Users, Registered Users 2 Posts: 3,916 ✭✭✭John.G


    Wearb wrote: »
    The shaft of the pump must be horizontal, which in this case it seems to be, but the photo might be confusing.

    Ah yes I see what you mean now, because of the picture's orientation the pump seems to have been installed vertically!.


  • #119
    corkgsxr
    Registered Users, Registered Users 2 Posts: 3,388 ✭✭✭corkgsxr


    John.G wrote: »
    Ah yes I see what you mean now, because of the picture's orientation the pump seems to have been installed vertically!.

    Yep. Which wears the bearings faster and traps air easier.


  • #120
    Blowheads
    Registered Users, Registered Users 2 Posts: 437 ✭✭Blowheads


    Ok, the frost stat was set to -4, I've set that to +4 now.

    I turned up the frost stat and pump and boiler ran, water through the bypass as all other valves were off. Water got hot v quickly and boiler shut off but pump kept running. I don't think this was directly related to recent events because there was no frost

    I also checked the hole for the stat/high limit, it seemed clean enough

    Since I started this thread it hasn't tripped once

    Back to the pump orientation, which way should the air nut be facing? Out towards me or up to the sky?


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  • #121
    John.G
    Registered Users, Registered Users 2 Posts: 3,916 ✭✭✭John.G


    Blowheads wrote: »
    Ok, the frost stat was set to -4, I've set that to +4 now.

    I turned up the frost stat and pump and boiler ran, water through the bypass as all other valves were off. Water got hot v quickly and boiler shut off but pump kept running. I don't think this was directly related to recent events because there was no frost

    I also checked the hole for the stat/high limit, it seemed clean enough

    Since I started this thread it hasn't tripped once

    Back to the pump orientation, which way should the air nut be facing? Out towards me or up to the sky?

    Last item first... your picture1 post 23 shows up on my Laptop as having the boiler lying on its side so I saved in some other programme and the rotated it 90 deg to show the boiler in its upright position (which is the way it was installed!) with the pump installed correctly ie, horizontally so there is no problem whatsoever regarding this, and yes, with vent screw facing out.

    The frost protection (including by pass) seems to be operating exactly as designed so that's another item put to bed.

    With the oil fired boiler only in service are all your rads heating up quickly and
    uniformly. If they are than that would indicate that the circulation is OK.
    However, if you, I would remove all the pipework between the pump flow side and the boiler, remove the 3 non return valves or whatever load of fittings are there and install a swing check type NR valve horizontally in a portion of copper pipe between the AAV (definitely renew this as well) and the boiler with the arrow on the NR valve pointing away from the boiler and have that bit of pipework very slightly inclined towards the boiler thus ensuring that the NR valve will swing shut.
    You might also consider going for broke and install a new circ pump, maybe a Grundfos UPS2 or a Wilo Yonis Pico 1-6.

    Lastly as suggested a few times in previous posts, before doing anything I would certainly try and record/measure the flow temperature and ideally the return temperature as well.


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