My stove has been plumbed up to a thermal store without a vent. The plumber originally had one and the system didn't work by gravity so when he put the pump on to circulate the water it must have pumped out the vent and he just cut it off and blocked it. I got another plumber to look at it who said it's not safe don't light the stove. The owner of the thermal stores said it's ok because the thermal store has a expansion vessel and it doesn't matter unless the electric goes out.
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It's an unvented cylinder, which shouldn't have an uncontrolled heat source attached to it directly.
Sounds like the plumber hadn't a clue.
And whoever from the manufacturer that said the expansion vessel is a safety feature, is an idiot.
Looks to me the primary flow is coming from overhead and therefore has to have its own vent pipe, no matter if that is actually a thermal store.
The expansion vessel does look like a stainless steel vessel for mains pipe like on some thermal stores. Needs more photos
And whoever from the manufacturer that said the expansion vessel is a safety feature, is an idiot.
Looks to me the primary flow is coming from overhead and therefore has to have its own vent pipe, no matter if that is actually a thermal store.
The expansion vessel does look like a stainless steel vessel for mains pipe like on some thermal stores. Needs more photos
That other pic makes it look like the pipe is coming out of the top of the vessel but it's not. Here's a better one
Need more photos of rest of lower cylinder and its pipes.
If there is any little red headed valves (pressure relief valves - PRVs ) with pipes coming out of them (normally 2 on unvented units) and a tundish (usually black coloured plastic open fitting on a discharge pipe. Plus any large valve. All those would prove it is unvented unit, if they exist.
- May 23, 2015
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Although it looks like an unvented cylinder, with some incorrect plumbing, it could be a vented thermal store with some sort of internal transfer coil for the mains water in (to high pressure hot out). Some thermal stores don't have an external heat exchanger.
The photos are difficult to decipher, but that looks like a vent pipe for that cylinder in middle and the expansion vessel looks like a small (stainless steel?) vessel for the mains supply pipe and coil only.
But I could be wrong, so ask the manufacturer for exact type you have.
The unit might be direct connections for the stove (they can be indirect also) and looks like your plumber altered the return to put a pump on. If the cylinder is designed for connecting a stove, then the stove pipes should have worked solely on gravity (no pump) and should have had an open vent. I assume the pump to the right side at the wall is the outlet pump to rads.
Get another heating engineer who actually knows about solid fuel pipes, as it is clear your plumber hasn't done it right.
Your manufacturer advice might have been correct about the cylinder being suitable for a stove (if it is a vented thermal store), but the statement about the lack of vent on the stove is wrong, as it requires it. Manufacturer might be confused plus inexperienced with pipework from a stove.
Only an idiot would cap that vent and add a pump on the primary return. Would be scary if pump fails!
If it is a vented and direct connections thermal store, then it is an easy set up, - stove gravitates to cylinder and radiator pump works on and off through a thermostat as heat rises and falls, but if it was an unvented unit, then a stove shouldn't be connected at all.
Let us know the manufacturer exact details of that cylinder.
The photos are difficult to decipher, but that looks like a vent pipe for that cylinder in middle and the expansion vessel looks like a small (stainless steel?) vessel for the mains supply pipe and coil only.
But I could be wrong, so ask the manufacturer for exact type you have.
The unit might be direct connections for the stove (they can be indirect also) and looks like your plumber altered the return to put a pump on. If the cylinder is designed for connecting a stove, then the stove pipes should have worked solely on gravity (no pump) and should have had an open vent. I assume the pump to the right side at the wall is the outlet pump to rads.
Get another heating engineer who actually knows about solid fuel pipes, as it is clear your plumber hasn't done it right.
Your manufacturer advice might have been correct about the cylinder being suitable for a stove (if it is a vented thermal store), but the statement about the lack of vent on the stove is wrong, as it requires it. Manufacturer might be confused plus inexperienced with pipework from a stove.
Only an idiot would cap that vent and add a pump on the primary return. Would be scary if pump fails!
If it is a vented and direct connections thermal store, then it is an easy set up, - stove gravitates to cylinder and radiator pump works on and off through a thermostat as heat rises and falls, but if it was an unvented unit, then a stove shouldn't be connected at all.
Let us know the manufacturer exact details of that cylinder.
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Could be a thermal store. The pump to the right is I guessed for to rads and just noticed writing on switch confirms that.
So could be stove primaries to the left, (maybe direct connections) and direct flow and return to rads on the right of cylinder.
Mains is perhaps going into an internal transfer coil for hot out. Vessel is misleading as it might be just for the mains pipework, not the cylinder.
If I guessed correct, then seems the plumber messed up with poorly done gravity piping layout for stove and added the other red pump and plugged the stove vent. Unbelievable! 😵
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The new plumber wants to move the cylinder into attic and make it work on gravity. I take it you agree with him.
The rep said gravity is no good now for the amount of power stoves is putting out and the pump works better as it agitates the tank.
The top left is feed from stove, bottom left with pump is return. When tank gets to 70 degrees it pumps water to rads to cool it down and stove brings it up again and repeats cycle to heat rads but it's rubbish and doesn't put out enough heat
- May 23, 2015
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Is the stove on same floor level as the cylinder? Like in a bungalow? The cylinder would need raised very high and not ideal. Really needs in a higher floor, but if attic is the next level, then I wonder how is that thermal store fed, as tank supply has to be much higher than the unit.
A combination thermal store has its own built in supply tank and is more suitable.
Gravity pipes should work well if done correctly. And I wouldn't use 90 degree bends where possible and just machine bend every bend on the primaries.
I hope the primaries don't have a long run?
Yes it's a bungalow and cylinder is on same level. The return from tank to stove is actually lower at the tank than the stove. The stove hot side goes into attic/attic conversion and travels about 12 feet to outside the attic truss, it then travels 28 ft along the house all at a slight ride to probably 1ft maybe slightly more. That is where the pipe for vent has been cut off from above and it then seems to drop straight down that foot again and comes across trusses about 10ft before dropping into tank. I think all bends are 90 degree bends
It's a fitted 90 degree where it comes up from stove. A 90 degree bend at end of 12ft and a fitted t at the end of 28ft.
There is a header tank or something above attic truss with 4 pipes going in and a plastic 5th probably over flow.
There is a header tank or something above attic truss with 4 pipes going in and a plastic 5th probably over flow.
That is a fairly long run, but not extreme.
The return connection at the cylinder would have ideally needed to have been at height of the stove or near it at a minimum. Sometimes that can be achieved by raising a cylinder on (needs substantial strong base, often fixed to supports from walls) to near ceiling level.
The return pipe itself can drop lower and only matters that it has a continual rise back to boiler.
Bends on the primaries should be machine bent where possible, or two 45 degree bends can be used.
The return connection at the cylinder would have ideally needed to have been at height of the stove or near it at a minimum. Sometimes that can be achieved by raising a cylinder on (needs substantial strong base, often fixed to supports from walls) to near ceiling level.
The return pipe itself can drop lower and only matters that it has a continual rise back to boiler.
Bends on the primaries should be machine bent where possible, or two 45 degree bends can be used.
Often easier to take the time to bend pipes for a skilled plumber rather than have to attempt awkward soldering of elbows, which are in fact not as good as more restrictive
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