Back boiler heating system

Blondie4321

I recently renovated a house and installed a Stanley stove with a back boiler. It drives 12 radiators. When I light a fire and it begins to heats up it makes a lot of noise, like water boiling behind it. It then levels off and quietens down, until I fill it again, noise again, then quietens again. I’ve never had a back boiler before, is this normal?

jimf

where is your stat for operating the pump situated


and what is it set to

Blondie4321

I think in the hot press but I don’t know what it’s set to, I know it’s prob hard to answer but do u think it should be higher or lower? It’s just I don’t understand the mechanics of it so I’m afraid it’ll explode! I’m prone to dramatics maybe...

jimf

it sounds as if

a your stat is too far from the stove

b it is set too high


your circulating pump is not being activated soon enough

bunderoon

As above. And it will be in the hotpress.

One or more of the following:

1) The stat is up too high - About >70
2) The stat is too far away from the return from the water tank so the stat is reading the temp incorrectly. The stat should be as close to the tank on the return pipe (return pipe to the stove) as possible.
3) The fire is on far to high (too much air flow - baffle open way too much) and the water cannot naturally rise and get over to the tank fast enough so it starts to boil in the boiler in the stove.

I am not a plumber but I went through some of the above myself.

Our stat is placed about 1.5m on the return pipe which means that while its about ~70 in the hot water cycliner, the stat needs to be set at 50 for the 'sweet spot'. When that temp hits, the water is then diverted to the radiators.

Blondie4321

Thank you so much for that info. I doubt it’s ‘a’ as a very good/reputable plumber installed the system and I trust him implicitly. So maybe it’s ‘b’. Excuse my lack of knowledge, but does that basically mean if I lower the stat the rads will be activated quicker? And back to my original question, if it’s noisy is it dangerous?

Blondie4321

The hot press is about 12-14 feet from the stove. Yes, the fire is on high, but it seems to take that for the rads to kick in?

agusta

bunderoon wrote: »

As above. And it will be in the hotpress.

One or more of the following:

1) The stat is up too high - About >70
2) The stat is too far away from the return from the water tank so the stat is reading the temp incorrectly. The stat should be as close to the tank on the return pipe (return pipe to the stove) as possible.
3) The fire is on far to high (too much air flow - baffle open way too much) and the water cannot naturally rise and get over to the tank fast enough so it starts to boil in the boiler in the stove.

I am not a plumber but I went through some of the above myself.

Our stat is placed about 1.5m on the return pipe which means that while its about ~70 in the hot water cycliner, the stat needs to be set at 50 for the 'sweet spot'. When that temp hits, the water is then diverted to the radiators.

the stat should be on the flow pipe

my3cents

Is there a plumber here that can explain how a good/reputable plumber can explain how this installation can be safe even if the pump/stat problem is sorted?

Doesn't sound right to me, what happens if the power goes and the OP has just banked the fire up?

bunderoon

agusta wrote: »

the stat should be on the flow pipe

You sure about that?

The stat is to divert water to the rads once the water in the water cycliner reaches a predetermined temp.
If the stat was on the flow pipe then the water wouldnt get diverted and the water would boil in the back boiler

jimf

my3cents wrote: »

Is there a plumber here that can explain how a good/reputable plumber can explain how this installation can be safe even if the pump/stat problem is sorted?

Doesn't sound right to me, what happens if the power goes and the OP has just banked the fire up?

this is why a solid fuel installation with boiler should have an unrestricted gravity circuit

bunderoon

Blondie4321 wrote: »

I recently renovated a house and installed a Stanley stove with a back boiler. It drives 12 radiators. When I light a fire and it begins to heats up it makes a lot of noise, like water boiling behind it. It then levels off and quietens down, until I fill it again, noise again, then quietens again. I’ve never had a back boiler before, is this normal?

Do you have heating zones (IE - Zone 1 = Bedrooms, Zone 2 = Living areas, Zone 3 = Hot water).

Big stoves will advertise that they heat 12 rads, but you would want a raging fire and kept well stocked for the 12 rads to be piping hot.

my3cents

jimf wrote: »

this is why a solid fuel installation with boiler should have an unrestricted gravity circuit

But no one has mentioned that yet? Getting the pump and stat fixed isn't going to fix an underlying safety issue.

jimf

my3cents wrote: »

But no one has mentioned that yet? Getting the pump and stat fixed isn't going to fix an underlying safety issue.

agreed

but none of us are on site so we can only answer the questions we are asked to the best of the information provided

agusta

bunderoon wrote: »

You sure about that?

The stat is to divert water to the rads once the water in the water cycliner reaches a predetermined temp.
If the stat was on the flow pipe then the water wouldnt get diverted and the water would boil in the back boiler

Yes
In a correctly fitted stove the water would not boil in the boiler.
Even in the event of a power failure

agusta

my3cents wrote: »

But no one has mentioned that yet? Getting the pump and stat fixed isn't going to fix an underlying safety issue.

I agree too

my3cents

jimf wrote: »

agreed

but none of us are on site so we can only answer the questions we are asked to the best of the information provided

But my understanding of the question was that the water is boiling in the back boiler because the pump isn't coming on. The problem is likely that the stat isn't triggering the pump because there is no gravity flow of water to move the heat along the pipes to wherever the stat is located. Getting the correct gravity feed going is part of fixing the problem.

jimf

bunderoon wrote: »

You sure about that?

The stat is to divert water to the rads once the water in the water cycliner reaches a predetermined temp.
If the stat was on the flow pipe then the water wouldnt get diverted and the water would boil in the back boiler

stat should be on the flow as near as possible to the stove

pump should be on the return

bunderoon

agusta wrote: »

Yes
In a correctly fitted stove the water would not boil in the boiler.
Even in the event of a power failure

Going off the OPs topic slightly, but just to explain - my stove has a gravity feed to the hotpress.
Then in the hotpress, there is a zoned manifold circuit. The pumps are for each zone and one pump for the stove aswell. In the case of a power cut, the water will still go up and over to the hotwater cylinder.

my3cents

bunderoon wrote: »

Going off the OPs topic slightly, but just to explain - my stove has a gravity feed to the hotpress.
Then in the hotpress, there is a zoned manifold circuit. The pumps are for each zone and one pump for the stove aswell. In the case of a power cut, the water will still go up and over to the hotwater cylinder.

Thats not really off topic because that is exactly how the OP's should work but the OP doesn't necessarily need separate zones.

In a two story building which the OP suggests they have a gravity circuit should be easy to set up so I don't see any reason for the water in the back boiler to be boiling (I'm assuming its not a pump snore problem - pump sucking air into the system because its pumping too fast).

agusta

bunderoon wrote: »

Going off the OPs topic slightly, but just to explain - my stove has a gravity feed to the hotpress.
Then in the hotpress, there is a zoned manifold circuit. The pumps are for each zone and one pump for the stove aswell. In the case of a power cut, the water will still go up and over to the hotwater cylinder.

what happens your system when you put on a big fire as in post 5

bunderoon

agusta wrote: »

what happens your system when you put on a big fire as in post 5

I never put on a big fire to start with. The position of the stove relative to the hotpress has meant that there are a fair few right angled joints on the gravity circuit to the hot water cylinder. In our case, starting a big roaring fire at the beginning will generate more hotwater in the stove that our gravity feed can handle. And I do mean a very large fire fed with too much air.

My routine if its of any benefit to the OP:
-Open the bottom and top baffles all the way.
- Start the fire with just kindling. After a couple of mins when half burned and hot (as hot as sticks would get), I then throw half a bucket of cozyglow in on it.
This just under half fills the stove.
- I leave this to burn and get to temp where the nuggets are red glowing. ~15 to 20mins. While that this is happening, the stove is pushing hot water to the water cylinder coil and colder water returns to the stove to repeat the process.
- Once the cozyglow is red hot, I put in another 1/4 of a bucket and a log and also close the baffles down by 3/4s the way.
This keeps the above going and eventually it will all reduce down to a super heated thick layer. Its at this time that the hotwater cyclinder is up to temp and the rads have kicked in (whichever zone is enabled at the time).
- After a few hours, top up the stove with another 1/4 bucket and when heading to bed, pop in another log. This will keep the bedroom rads piping hot until ~3am and slowly start to reduce the temp naturally after that (obviously).


To give the OP a rough idea, a 20KG bag of cozyglow (or whatever stove nugget - 20KG is about 8-10 euro) would do at least 2 nights fires. Add four logs to that aswell.

This is my stove:
https://www.woodburningstoves.com/olymberyl-stoves/olymberyl-aidan

In the link, you'll see that it says that it will heat 10-12 rads. You would want a raging fire, near constantly and kept topped up to get 10-12 rads piping hot and kept at that temp.
If you dont have heating zones, then the next best thing would be rad thermostats so you can turn down the water going to less important rads.
As you can see, I am no plumber, but the above works best for us and some of it may help the OP.

demanufactured

OP,
Can you find where the pipe stat wh8ch controls your circulating ounp is located?

This should be on the flow (hot) pipe coming from the stove to the hotpress.
Once you find it let us know what it's set to.

Is your house a bungalow or 2 storey?
Where is the hotpress in relation to the stove?

my3cents

demanufactured wrote: »

OP,
...
Is your house a bungalow or 2 storey?
...

Good point I misread "The hot press is about 12-14 feet from the stove" as above stove