Extra pump on heating system

Smellfie

Hi, a question about a little job I'm doing in my house at the moment.

I'm converting a shed at the back of the house into living quarters for my daughter.
All the services will be taken from my house but I estimate the heating pipes will be approx
30m in length to get to the shed, which will have three average rads in it.

My boiler is maybe 15+ years old, no make on it that I can see but it's a system boiler so has a pump built in.
I'm not sure if it will be strong enough to pump out to the shed and back again.

I'll be connecting up to the existing heating system first to see how it runs but
is it possible to put an extra pump on the shed pipes to give them a kick if needs be?

Sleeper12

Smellfie wrote: »

Hi, a question about a little job I'm doing in my house at the moment.

I'm converting a shed at the back of the house into living quarters for my daughter.
All the services will be taken from my house but I estimate the heating pipes will be approx
30m in length to get to the shed, which will have three average rads in it.

My boiler is maybe 15+ years old, no make on it that I can see but it's a system boiler so has a pump built in.
I'm not sure if it will be strong enough to pump out to the shed and back again.

I'll be connecting up to the existing heating system first to see how it runs but
is it possible to put an extra pump on the shed pipes to give them a kick if needs be?

Id be much more worried about the heat loss getting from your house to the daughters granny flat.
A 30 metre run. I'm pretty sure it would be like heating 6 rads instead of 3. I would think it would be more cost effective to put in a small boiler in the granny flat.
I'm sure some rgi guys on here will know more.

Smellfie

Pipes will be well insulated, good high temp stuff wrapped in plastic and put in a duct.
Boiler is not really an option as the garden between the house and shed will be landscaped when finished so nowhere really to hide oil tank or gas bottles. Mains gas also not an option.

Egass13

Smellfie wrote: »

Pipes will be well insulated, good high temp stuff wrapped in plastic and put in a duct.
Boiler is not really an option as the garden between the house and shed will be landscaped when finished so nowhere really to hide oil tank or gas bottles. Mains gas also not an option.

You'd be wasting your time IMO . How come mains gas isn't an option? Your probably better off with a few storage heaters in that case

K.Flyer

If Gas or Oil is definitely out of the question then my advise would be to spend your money on getting the place well insulated and using a couple of small room heaters.
What were your plans for hot water as a 30m run is a huge waste of water waiting for the hot water to reach the tap.

Sir Arthur Daley

To use a pipe e.g Armacell would give very little heat loss would it not and could another cylinder be installed locally for hw?

Smellfie

Thanks for the replies:

Mains gas not really an option because our boiler and meter box are both at the front of the house.
House is mid-terraced so only way to route gas would be through the house which would cause too much disruption.

Hot water will be from undersink water heater and an electric shower.

Are peoples main concerns the circulation or heat loss or both? Like I said pipes will be insulated
as best I can with good insulation. And it's not going to be a permanent situation, in a year or two
hopefully she'll be able to get her own place.

The circulation is the one that's troubling me the most. Is 30m too much of a run? And does anyone know
if an extra pump is possible if needed?

Egass13

Smellfie wrote: »

Thanks for the replies:

Mains gas not really an option because our boiler and meter box are both at the front of the house.
House is mid-terraced so only way to route gas would be through the house which would cause too much disruption.

Hot water will be from undersink water heater and an electric shower.

Are peoples main concerns the circulation or heat loss or both? Like I said pipes will be insulated
as best I can with good insulation. And it's not going to be a permanent situation, in a year or two
hopefully she'll be able to get her own place.

The circulation is the one that's troubling me the most. Is 30m too much of a run? And does anyone know
if an extra pump is possible if needed?

If boiler is a system boiler, the 2nd pump may affect the pump of the gas boiler. On a run like that though, a low head pump should be fine as long as the system is pressurised. If boiler pump is on the return, then have the new pump on flow to rads assisting the existing set up, not against it. Also use a zero loss pipe , such as calpex or similar

Smellfie

Egass13 wrote: »

If boiler is a system boiler, the 2nd pump may affect the pump of the gas boiler. On a run like that though, a low head pump should be fine as long as the system is pressurised. If boiler pump is on the return, then have the new pump on flow to rads assisting the existing set up, not against it. Also use a zero loss pipe , such as calpex or similar

Thanks Egass........could you post a link to a pump you think would be suitable?
How would I know if the existing pump is on the flow or return? Would I need an Rgi to check?

Egass13

Smellfie wrote: »

Thanks Egass........could you post a link to a pump you think would be suitable?
How would I know if the existing pump is on the flow or return? Would I need an Rgi to check?

If it a system boiler it's most likely on the return , but just incase,What boiler have you got ? If there's no name just post a pic

Smellfie

Leave it with me, I'll try to get a pic up later.

Sleeper12

30M, is 30M there & another 30M back to the boiler thats a 60 meter run in total.
Just to give you an idea of how much water that is try this: wait till the water in your hot pipe from the cylinder is cold but plenty of hot water in the cylinder. Go to your kitchen tap & run the hot but collect it in a pint glass or jug. When full empty it & fill again. Do this till you have hot water. The average pipe from the cylinder to the kitchen tap holds 5 or 6 pints of water. Thats only from cylinder upstairs to kitchen sink downstairs.

There would be huge heat loss on an outside run but even ignoring that its all the water in the pipes on the 60m return journey. It would be like trying to heat another few rads. You might even discover that your boiler is undersized for it. Someone picked a boiler size suitable for your house needs. Its unlikely its big enough to do what you want it to do.

A point an the electric shower just in case her electric supply will be off your house & in case you have an electric shower yourself. You can only run 1 electric shower at a time in a house as they use so much electricity. If you run 2 at the same time you run the risk of blowing the main fuse in your house. Not the one at your fuseboard that you just flick up but the ESB fuse for your house. If this blows you have to wait for the ESB to come out to repair it.

I suggest you get a RGI to look over your boiler & get his advice about the heating.

Smellfie

Hi thanks for replies.

I got a plumber/rgi to look over the existing system and proposed extension to the system and he is of the same opinion that the run is very long and no guarantee how well it will work. So we've decided to go with an lpg boiler with the gas bottles hidden behind some trellis fence.

As we will only have 3 rads in the granny flat I thought the smallest boiler would have been best but the rgi suggested a 24kw boiler as it modulates down to 8kw and would be cheaper to buy as its more mass produced than the smaller boilers. Is he right?

I really don't need this thing costing a fortune to run. The boiler he mentioned was a "Baxi Megaflow Compact Ga" which can be run on mains gas or lpg at the touch of a button apparently. Is this a good boiler?

Egass13

Smellfie wrote: »

Hi thanks for replies.

I got a plumber/rgi to look over the existing system and proposed extension to the system and he is of the same opinion that the run is very long and no guarantee how well it will work. So we've decided to go with an lpg boiler with the gas bottles hidden behind some trellis fence.

As we will only have 3 rads in the granny flat I thought the smallest boiler would have been best but the rgi suggested a 24kw boiler as it modulates down to 8kw and would be cheaper to buy as its more mass produced than the smaller boilers. Is he right?

I really don't need this thing costing a fortune to run. The boiler he mentioned was a "Baxi Megaflow Compact Ga" which can be run on mains gas or lpg at the touch of a button apparently. Is this a good boiler?

A plumber suggesting a 24kw boiler for 3 rads?? I'd part company with him before this even starts .
Baxi megaflow ga , not what if go for .
Most , if not all boilers can be simply coverted for use with LPG . You need the smallest one you can get , which of the top of my head is 12kw, and even that's oversized. Is there any hot water requirement?

Smellfie

I did think 24kw was too big myself but when he said it modulates down to 8kw I thought maybe that's just the way things are done.

No requirement for hot water as we will use an undersink water heater for basin and kitchen sink. Shower will be electric fed from mains water.

As the boiler is an after thought I did say to him to try and keep it on the more affordable side so maybe that's why he choose the Baxi boiler. From my little bit of research they do seem to be cheaper.
Any boiler recommendations? Bearing in mind money is tight and in a couple of years the daughter may have moved out.

This plumber has only got to price the job, nothing agreed. My friends nephew whose a plumber is calling in before the end the week to have a look and give me a price. Just want to arm myself with a bit more knowledge on the heating side of things.

Smellfie

Smellfie wrote: »

Hi thanks for replies.

I got a plumber/rgi to look over the existing system and proposed extension to the system and he is of the same opinion that the run is very long and no guarantee how well it will work. So we've decided to go with an lpg boiler with the gas bottles hidden behind some trellis fence.

As we will only have 3 rads in the granny flat I thought the smallest boiler would have been best but the rgi suggested a 24kw boiler as it modulates down to 8kw and would be cheaper to buy as its more mass produced than the smaller boilers. Is he right?

I really don't need this thing costing a fortune to run. The boiler he mentioned was a "Baxi Megaflow Compact Ga" which can be run on mains gas or lpg at the touch of a button apparently. Is this a good boiler?

That's like trying to get a elephant into a rabbit hutch, it ain't going to fly.

I'd get a another RGIs opinion/quote if I were you.

I haven't seen any in homes in Ireland but what about wall mounted heaters:https://www.thegascompany.ie/iopen24/gas-home-wall-heaters-designer-c-1326_1779_1781.html

Smellfie

Is he totally wrong then with his modulation quote? I'll pull him up on it if he is, don't like people spinning me yarns

Smellfie

Smellfie wrote: »

Is he totally wrong then with his modulation quote? I'll pull him up on it if he is, don't like people spinning me yarns

He'll have to commission it as a 24kw and with 3 rads he'll be finished in time to let your grandkids move in.

corkgsxr

Egass13 wrote: »

A plumber suggesting a 24kw boiler for 3 rads?? I'd part company with him before this even starts .
Baxi megaflow ga , not what if go for .
Most , if not all boilers can be simply coverted for use with LPG . You need the smallest one you can get , which of the top of my head is 12kw, and even that's oversized. Is there any hot water requirement?

The 28 kw worchester Bosch junior combi will modulate down to 7 kw. And comes in log

(Just saying the the 28 cos I know the figures)

Smellfie

gary71 wrote: »

He'll have to commission it as a 24kw and with 3 rads he'll be finished in time to let your grandkids move in.

^^ I don't really understand what that means but presume it's not good.

Thanks for the suggestion of wall mounted heaters but they seem pricey and I'd prefer not to be someone's guinea pig!!

Dtp1979

Smellfie wrote: »

^^ I don't really understand what that means but presume it's not good.

Thanks for the suggestion of wall mounted heaters but they seem pricey and I'd prefer not to be someone's guinea pig!!

It means that if u fit a 24kw it fires at 24kw then modulates down after a while. Why would u want 24kw burning when you probably need 5-6 kW?
When he's commissioning the boiler, it will be very hard because the rads will be hot in 2 mins and the boiler will stop therefore making commissioning difficult

Smellfie

Do the new boilers actually stop or just go to a really low flame when up to temperature?

Smellfie

Smellfie wrote: »

^^ I don't really understand what that means but presume it's not good.

Imagine you had a elephant, now imagine you have a rabbit hutch, now imagine trying to get that elephant into the rabbit hutch. Now replace the elephant with the 24kw output of the boiler and the rabbit hutch with your 3 rads.

Smellfie wrote: »

Thanks for the suggestion of wall mounted heaters but they seem pricey and I'd prefer not to be someone's guinea pig!!

Wall mounted heaters are well proven and common place in London where hot water is supplied by multipoint water heaters and heating by the wall mounted heaters, the wall mounted heaters just aren't really used here but work perfectly well.

Smellfie

Seems like I'm shopping at the Baxi & Glow worm end of the market. Would people have a preference?

Ariston gets mentioned a lot in this forum but the smallest boiler they seem to do is 18kw.

Egass13

corkgsxr wrote: »

The 28 kw worchester Bosch junior combi will modulate down to 7 kw. And comes in log

(Just saying the the 28 cos I know the figures)

I'm not debating the fact the boiler modulates , but without out getting technical about it , if it were that simple then why make a 12,15,18,24kw versions. Sure by that logic it would be a one size fits all .

Smellfie

Smellfie wrote: »

Seems like I'm shopping at the Baxi & Glow worm end of the market. Would people have a preference?

Ariston gets mentioned a lot in this forum but the smallest boiler they seem to do is 18kw.

Whatever boiler you get the gas pipe must be sized to fed the boiler at its highest output, the installer can get around the higher output by fitting a temporary heat dump and then finally range rating the boiler to match your lower demand.

You can archive what you wish but you need a installer that's switched on or it can end in tears.

corkgsxr

Egass13 wrote: »

I'm not debating the fact the boiler modulates , but without out getting technical about it , if it were that simple then why make a 12,15,18,24kw versions. Sure by that logic it would be a one size fits all .

I'm in similar situation but not half as bad. Iv a 28kw worcester junior combi.

Brilliant for the hot water but only serves 5 rads.

Admittedly it's

One 6x1200 towel
1 1000 s
1 1000 d
2 1300 d

corkgsxr

corkgsxr wrote: »

I'm in similar situation but not half as bad. Iv a 28kw worcester junior combi.

Brilliant for the hot water but only serves 5 rads.

Admittedly it's

One 6x1200 towel
1 1000 s
1 1000 d
2 1300 d

I'v got 250,000BTU oil boiler, err... Nobody told me they don't bloody modulate, I hate oil:mad:

corkgsxr

gary71 wrote: »

I'v got 250,000BTU oil boiler, err... Nobody told me they don't bloody modulate, I hate oil:mad:

Ya sure? 73kw. I want your house

corkgsxr

corkgsxr wrote: »

Ya sure? 73kw. I want your house

I didn't say I had a 73kw requirement (I prefer BTUs cos it's more dramatic) you can take that 73kw, half it then half it again DOH...... I never said I was clever:o

Dtp1979

Smellfie wrote: »

Seems like I'm shopping at the Baxi & Glow worm end of the market. Would people have a preference?

Ariston gets mentioned a lot in this forum but the smallest boiler they seem to do is 18kw.

You can adjust the max output of the Ariston so it may well suit your situation. Also it's a great boiler and very well priced