Boiler Not Heating Hot Water Cylinder

Sierra Oscar · 25-10-2011 11:51pm #1

Hey all, just looking for some advice! For the last number of days now it seems that my gas boiler is no longer heating my hot water cylinder. The immersion heater for the cylinder is working however.

I think it may have something to do with one of the water pumps / valve shut-off devices, pictured below (I am not exactly sure what it is!). That device is located on the inlet pipe from the boiler to the cylinder.

http://i132.photobucket.com/albums/q3/Sierra_Oscar_2006/IMG_0382.jpg

I am saying this because when I moved the switch on the device to the manual override position (pictured here) the water started to heat. It was on the automatic side when I first looked at it. Also there is an orange light displaying on the unit, is that normal?

Just wondering if anyone has any opinions.

JohnnieK · 26-10-2011 12:09am

That device is the zone valve and the blue box is the actuator (motor and microswitch) I would hazard a guess the actuator needs to be replaced. That brand is poor quality. They can be replace with a brand called Sauter which are a bit better.

Sierra Oscar · 26-10-2011 12:24am

Thanks Johnnie, Ill look into that. For now is it OK to leave it on the manual override function? That seems to allow the water to be heated.

bks · 18-02-2012 9:04pm

Hello Guys,

I have similar problem, where water is not heating but the rads are. Already two plumbers visited and spend a lot money already. Both of them telling that, there is blockage in the pipe somewhere due to Lime scale deposit. Today the second plumber tried to clear up some deposits from pipe in and around the press, but no joy yet, still water is not heating, but thankfully immersion is working , so I have hot water. Now, plumber is suggesting that for the next step, floor board has to come out from Press to chaeck the blockage in under floor pipes. But not giving any assurance that it would be sorted out, it might need to take out other floors in other rooms as well , alreday spent 300 euro in two call out charges and todays 2 hours of work. Plumber is saying that if not sorted out then boiler will be affected and will cost lost more.

in My press, I do not see any such equipment like Sierra Oscar's . Please help me out I am almost broke, two months ago lost job and deep in trouble now..... Please please help me out......Would appreciate...

For info: my boiler is Vokera and 9 years old.

shane0007 · 18-02-2012 10:16pm

Do you have a zone valve similar to Sierra Oscar on the cylinder pipework in the hotpress? They may not look like those, but will be very similar, they could be white, yellow, metallic, etc.

It sounds like a similar issue. It could also be a faulty cylinder thermostat if you have one fitted. Simple continuity or resistance tests can eliminate those. Another possibility is a faulty timeclock if you have a multi-zone programmer; the hw section of it could be faulty.

Sierra Oscar · 18-02-2012 10:44pm

Just an update on what was wrong with my system - the actuator was broken. The plumber just removed it altogether and all is good now.

shane0007 · 18-02-2012 10:51pm

Why remove it all together? Was it not wired back to the boiler through it's auxillary? By having a motorized valve there you are saving money as if it is wired correctly in conjunction with a cylinder thermostat, once the water reaches 60C, it will turn off that circuit and the boiler, saving you €'s, instead of continously heating the cylinder when all you may require is radiator heat.

All that was needed was a valve head replacement. The system would not even have to be drained!

heinbloed · 18-02-2012 11:00pm

Shane0007 wrote in response to the OP:

Was it not wired back to the boiler through it's auxillary? By having a motorized valve there you are saving money as if it is wired correctly in conjunction with a cylinder thermostat, once the water reaches 60C, it will turn off that circuit and the boiler, saving you €'s, instead of continously heating the cylinder when all you may require is radiator heat.

If the cylinder is used as a thermal buffer (as frequently done with oversized boilers) a thermostatic valve interfering with the continous buffering would
cost a lot of money, fuel and running hours.
This might be the reason for the plumber's action.

shane0007 · 18-02-2012 11:04pm

I am not talking about a thermostatic valve. I said a cylinder thermostat. This will break the switched live to the motorized valve thus breaking the switched live to the boiler thus turning off the boiler. This is commonly known as boiler interlock and Building Regulation requirement.

JohnnieK · 18-02-2012 11:31pm

bks wrote: »

For info: my boiler is Vokera and 9 years old.

The boiler is not the problem here.

Do you get flow through the heating coil on the cylinder when all radiators are turned off?

If not could there be a manual valve closed?

It must be some restriction if it preventing movement through the coil.

Can you post some pics?

heinbloed · 18-02-2012 11:34pm

The thermostat would cause the flow through the cylinder to be interrupted.
If this happens during the heating season (when most fuel is burned) the cylinder becomes more or less useless as a thermal buffer.

It will lose it's thermal buffering capacity because it would be isolated from the CH system then.

The building regulations certainly do not demand such an uneconomic space heating method. The guidelines to the building regulations (frequently taken as "the building regulations" by the amateurs) are not legally binding and state this as well.
The guidelines allow for a deviation of the guidelines for economic reasons. Funny enough, but read them yourself.

bks · 19-02-2012 9:28pm

Thank all of you who commented. I am a lay man in plumbing matter. To answer Shane, I do not see anything like hat Sierra has and do not find cylinder thermostatic valve either, how it looks and where should be situated, if there is any, I will try to post some photos tomorrow. Motorised valve, could it be inder floor floor board? Is MV standard fittings which new house builder had to do? (my house was built in 2003). is multizone programmer is a separate thing should be fitted someehere to contol the heating or it is a part of the boiler where you can programme?

JohnnieK, When you say water flow in heating coil, do you mean flow through the inlet pipe of the cylinder? or coild inside the cylinder ( unlikely) must be the through pipe, isnt it? I never tested by shutting off the rads, shall I do this test?

Does anyone think that lime scale deposit and blockage of the pipe is the problem in my case, what plumbers are telling me?

I will post more info after close observation.

JohnnieK · 20-02-2012 12:33am

@ bks.
Your cylinder has a coil inside it that the central heating is attached to, flow on top of the side of the cylinder and return on the bottom.

Turning off the radiators is an easy test to do and you will know if there is a blockage or not. The two pipes going into the side of the cylinder will get hot and you will have hot water after about 20 mins. They would be on the same side of the cylinder as each other one above the other.

If you do that with the radiators and nothing heats up then there is an issue, but again a picture or two would help.

shane0007 · 20-02-2012 12:35am

heinbloed wrote: »

The thermostat would cause the flow through the cylinder to be interrupted.
If this happens during the heating season (when most fuel is burned) the cylinder becomes more or less useless as a thermal buffer.

It will lose it's thermal buffering capacity because it would be isolated from the CH system then.

The building regulations certainly do not demand such an uneconomic space heating method. The guidelines to the building regulations (frequently taken as "the building regulations" by the amateurs) are not legally binding and state this as well.
The guidelines allow for a deviation of the guidelines for economic reasons. Funny enough, but read them yourself.

A domestic hw cylinder is NOT a thermal buffer. It is a domestic hw cylinder. Building Regulations clearly stipulate that when installed a heating system or when replacing a boiler, the heating system must have separate heating zones and a separate domestic hw zone. Each zone must have 7 day time and temperature control and wired to encorporate boiler interlock. Building regulations ARE legally binding and are reinforced by the Department of the Environment. They are not guidance documents. TGD's are guidance documents. I think the only amateur here is you.

JohnnieK · 20-02-2012 12:39am

@ shane00007 you are better off ignoring him:D:D:D:D

shane0007 · 20-02-2012 12:48am

JohnnieK wrote: »

@ shane00007 you are better off ignoring him:D:D:D:D

I know (gritting teeth...) but it is hard not to. I think I could end up with some counselling after him. What is hard to fathom is that all here seem to have one purpose, to give some helpful advice to people that are stuck, and his purpose is to hamper that help. Strange little person...

Billy Bunting · 20-02-2012 12:53am

JohnnieK wrote: »

@ shane00007 you are better off ignoring him:D:D:D:D

I do try. :rolleyes:

heinbloed · 20-02-2012 1:11am

Shane0007 wrote:

A domestic hw cylinder is NOT a thermal buffer. It is a domestic hw cylinder. Building Regulations clearly stipulate that when installed a heating system or when replacing a boiler, the heating system must have separate heating zones and a separate domestic hw zone. Each zone must have 7 day time and temperature control and wired to encorporate boiler interlock. Building regulations ARE legally binding and are reinforced by the Department of the Environment. They are not guidance documents. TGD's are guidance documents. I think the only amateur here is you.

Well, literacy is demanded when trying to understand a document. To see what we are talking about I link the relevant ducument:

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,27316,en.pdf

and quote from it:

1.4.2 Heating appliance efficiency
1.4.2.1 The appliance or appliances provided
to service space heating and hot water
systems should be as efficient in use as
reasonably practicable.

Taking an (insulated buffer-)tank -and any water storage in a CH system is a thermal buffer as long as connected - out of operation is unreasonable as long as the boiler's output is oversized.

The building regulations are enhanced in grey (see link provided) on page 5.
The rest of the text (black on white) are the "technical guidelines".
These guidelines are NOT legally binding, see the comment 1.4.2 quoted from the guidelines. A reasonable comment, b.t.w..

The term " reason " might need an interpretation for the amateur, but that would be a different thread altogether.

This interpretation would help to understand the legally binding building regulations, I quote :

L1 A building shall be designed and constructed so as to ensure that the energy performance of
the building is such as to limit the amount of energy required for the operation of the building
and the amount of carbon dioxide (CO2) emissions associated with this energy use insofar
as is reasonably practicable.

As the reader can read in the official document - if competent to do so - the reasonable practicability in terms of energy performance and CO2 emission reduction is legally demanded.
Not a controlled heating system per se. Certainly not in the Irish building regulations.

20-02-2012 1:12am

20-02-2012 1:13am

shane0007 wrote: »

I know (gritting teeth...) but it is hard not to. I think I could end up with some counselling after him. What is hard to fathom is that all here seem to have one purpose, to give some helpful advice to people that are stuck, and his purpose is to hamper that help. Strange little person...

He's just a bloke with a computer who has no experience so can't put together the information he keeps trying to play with.

shane0007 · 20-02-2012 1:26am

So bright boy, why was there legal action taken in the case of Priory Hall?

I think you need to dig deeper than that document to fully understand the regulations.
http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,18691,en.pdf

This document spells it out as to what is a minimum requirement and what is a recommended requirement.

BTW the only water that is part of the heating system within a dhw cylinder is with the coil itself and it is not there to store energy but to transfer it. DHW is not used to give it back to space heating but to be store for erm... em DHW.

Cedrus · 20-02-2012 1:31am

Sierra Oscar wrote: »

Just an update on what was wrong with my system - the actuator was broken. The plumber just removed it altogether and all is good now.

The "plumber" has removed your automatic zone control and knocked several points off your BER cert. Those actuator are s**** but are easily replaced with a better quality such as sauter, the wiring can be a bit of a nightmare which may be why he just stripped it. I've replaced 4 of them in my house before I copped on that it was an inherent quality issue rather than just random duff ones.

shianto · 03-01-2013 8:33am

Folks I realise this is quite an old thread now, but I am hoping some of you more knowledgeable contributors could help...

I have my hotwater tank on a separate circuit to the heating (gas boiler). The cylinder also has a separate electric immersion element (actually technically two i.e. sink and bath). Up until just before Christmas the gas had always heated fine, and the we started to notice it becoming cooler and cooler. Then it stopped heating altogether. Being Christmas I took the lazy man's option. Switched off the hotwater gas heated circuit (other heating circuits working fine BTW) and switched on the electric. Which was working ok until last night..now that has stopped!

I am guessing it must be to do with the tank and there is a small amount of water leakage around the electrical immersion element at the top (just slightly damp). I have tried to do a bit of research online but cannot see a definitive answer. Any suggestions?

Many thanks

martina11457 · 27-09-2014 10:57pm

Hope someone can help.my heating tank was banging,then the pump stopped,thought i had airlock, bleed the rads,now i hav no heat as the pressure went.the last time the gas company was out for boiler service i ask him to look at ccynliner and he said that the trv on the hot water cynlinder is fitted wrong way round and pipe work is wrong way round as well.hav i any come bk as i bought my apartment not noing this

JohnnieK · 28-09-2014 10:32am

martina11457 wrote: »

Hope someone can help.my heating tank was banging,then the pump stopped,thought i had airlock, bleed the rads,now i hav no heat as the pressure went.the last time the gas company was out for boiler service i ask him to look at ccynliner and he said that the trv on the hot water cynlinder is fitted wrong way round and pipe work is wrong way round as well.hav i any come bk as i bought my apartment not noing this

How long ago did you buy your apartment?

There should be a device in your hotpress to re pressurize your heating system. It's possible that it is a silver braided hose with a valve on one side.

If you can't locate it take some pics and put them up.

On a sealed system like you have it is not really important on flow and return at the cylinder, that rule was more for open system's. It would still be good working practice to have the flow at the top but not essential.

martina11457 · 28-09-2014 1:38pm

Thanks for quick reply.thats grand noing that trv is okay even if it is in wrong place,the gas fella said it would cause problems later on.i was looking at a bidirectional trv danfoss ras-c revolver that could correct this.yes i hav pressure loop and when i turn it their is no water coming out,could der b airlock in cynlinder or pipes

JohnnieK · 28-09-2014 1:55pm

martina11457 wrote: »

Thanks for quick reply.thats grand noing that trv is okay even if it is in wrong place,the gas fella said it would cause problems later on.i was looking at a bidirectional trv danfoss ras-c revolver that could correct this.yes i hav pressure loop and when i turn it their is no water coming out,could der b airlock in cynlinder or pipes

The tcv will still need to be turned around to suite the direction of flow.

I would imagine being an apartment the filling loop is attached to the cold circuit that is pumped by the apartment pump in the hotpress.

You might have to run the cold tap in the bathroom to activate the pump and then open the filling loop, ridiculous i know but a lot of them are done that way.

martina11457 · 28-09-2014 2:09pm

I hav a problem der, i hav cold water coming from mains under sink in kitchen,But i only hav hot water in bathroom.no cold,.tank god i hav immersion,hav to fill basin to fill bath with cold water from kitchen,i live in apartment. I dont no what to do first.and who to call in as it might not b pump

JohnnieK · 28-09-2014 5:49pm

martina11457 wrote: »

I hav a problem der, i hav cold water coming from mains under sink in kitchen,But i only hav hot water in bathroom.no cold,.tank god i hav immersion,hav to fill basin to fill bath with cold water from kitchen,i live in apartment. I dont no what to do first.and who to call in as it might not b pump

It might be the cold side of the pump. The kitchen sink is mains.
The rest of the colds are from the tank above the hot cylinder. What about the toilet? Is that filling?

The toilet could be fed from a separate feed from the tank.

Is it possible a valve was closed at the pump?

martina11457 · 28-09-2014 7:14pm

No toilet is not filling up either. Wer de valve at pump,is it de red wheel over de filling loop.yes toilet feed is de white pipe sticking out of cnyliner

JohnnieK · 28-09-2014 7:20pm

I'm going to need pictures I'm afraid.

Too many valves in a hot press to know for sure.

Boiler Not Heating Hot Water Cylinder

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