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Tl;dr:
Heating works with LPG boiler. Has stopped working with biomass heat store.
Also, how to upgrade to smart TRVs/pumps on this system.
Where to start?
First an admission: I'm inclined to overcomplicate things. Hopefully the combined brains of DIYnot will help me identify the simpler solutions.
Second: I apologise for the length of this post.
Background: Old house "YH" had Rayburn powering a gravity hot water system and a pumped radiator system. At some point an LPG boiler was added as a backup. Rayburn was undersized for old farmhouse so we tried to improve, however, a dodgy "Green" company installed undersized biomass furnace and heat store system and then went bust. Subsequently had to (re)install backup LPG boiler, to help with cold spells and being away from home etc.
I've also made some improvements to increase efficiency (bypass valve so we're not sending 70m of 4°c water through the radiators waiting for the hot water to arrive). But each of these systems has been partly appended to the previous system, such that we now have a non-standard system that upsets the local plumbers.
However, apart from being undersized, it has worked well for over 10 years (I've replaced odd parts here and there).
I need help with 2 issues that are different, but possibly one will affect the other, so I'm putting both here.
The second issue:
I can't afford to replace the biomass system with a correctly (larger) sized one. So I'm looking to improve efficiencies wherever I can. I now think I need to look at smart TRVs so we're not trying to heat the whole (very un-insulated) house because one room is cold.
The "easy" bit is to put in a smart circulation pump and TRVs that will work with the LPG boiler in the house.
The complicated bit is that the heat store is 70m away (and 5.5m below) the house circulation pump, so it has two pumps, one in the house and one by the heat store to bring (and return) the heat store water to the house system. I think these two pumps would need adjust their flow rates to match the house pump? How can these pumps speeds be adjusted together?
My overcomplicating mind sees a Home Automation solution with a central software program monitoring the hot water needs and sending the required speed control signals to each of the three pumps as required.
I think I can do this, but it makes the system reliant on the software which makes it inherently more complicated for future plumbers dealing with issues/repairs etc. And, software itself isn't always reliable anyway!
Is there any way to redesign the whole system to simplify these complications?
The primary issue:
When we fired up the biomass system last autumn - it isn't working properly.
When called for, the heat store pumps (P2 & P3) turn on and hot water arrives in the house system, however, the upstairs radiators get warm-ish, but the downstairs radiators stay cold - I know, a common problem with plenty of advice already available - However, all the radiators get hot when the LPG boiler is the heat source. So many of the usual suspects cannot apply here.
I've been through the whole system (and replaced various aging components) nothing has fixed this problem.
I can only imagine it's some kind of restriction in the flow from the heat store, but I'm not sure where/how that could be.
I suspect the pumps the dodgy biomass company installed didn't adequately allow for the friction loss of the pipe run, but they've just about managed it for the last 10 years. Now something is making that harder and it can't get enough flow.
I've tried to work out the required flows, but the pump and boiler companies just want to know what the existing pumps are (even if they're undersized) or to be given the correct specifications by the installer (various including dodgy and bust). The LPG boiler company won't tell me what the maximum and minimum flows are required for their boiler, so I don't know if any of the pumps are in the right range at all.
I'd love to find a local plumber/engineer to help with my Frankenstein's monster of a system, but I live in very rural mid Wales and haven't found a suitable person yet (please message me if you are this person!).
Information and things I have tried:
Please see attached pictures.
When the LPG boiler is going, the boiler overheats if Pump 1 (UPS 3 15-50/65) is on Constant Curve 1. CC 2 or 3 are fine, so the flow rate in the house system needs to be something above 1 m³/h.
2 - 2.5 m³/h seem to work well.
The biomass ultrasonic flow meter reading varies between 0.3 - 0.4 m³/h when it's going through the bypass valve. It drops to around 0.1 - 0.3 m³/h once the bypass valve closes and Pump 1 joins in to push it round the house.
All of these are too slow.
I've checked (and sometimes replaced) every pump, motorised valve, gate valve etc.
No repairs or replacements have made any difference.
I've bled the radiators (no air) and tried to identify where any other airlocks could be (I can't find any). There's no sign of sludge and very little debris in the Fernox TF1 filter or anywhere else in the system.
There are drain points at the lowest point in the cellar (~7.5m head from F&E tank). I've timed how long it takes to fill a 2 litre jug, without any pumps on, to check for obstructions in the pipes between the heat store and the heating system in the house (although I'm not sure where the obstruction would be):
The quickest (F&E tank > cellar drain ~30m) around 4 seconds.
The longest (F&E tank > heat store > cellar drain ~100m) around 30 seconds.
The timings are similar with the water flowing in either direction (normal flow direction or reversed).
I don't know if that tells me much more than the longer the pipe run, the lower the pressure?
The most curious question for me is what has changed? The system worked well enough for the last 10 years. Now suddenly it doesn't work although there's no clear fault with any individual part of the system.
Problems to solve:
What should the flow rate be for the LPG boiler?
What flow rate should the biomass pumps be supplying at the house?
Why aren't they? Or what is stopping them?
Once the biomass system is working again, what's the best way to upgrade the existing system to smart TRVs and pumps to allow for varying flow rates? Allowing for the long pipe runs, and 3 different pumps in 2 different locations.
Or, is there a completely different system design that would solve all the issues?
I again reiterate that I'd love to find someone local who can work with me on this, but failing that - You are my only hope!
Please help!
Heating works with LPG boiler. Has stopped working with biomass heat store.
Also, how to upgrade to smart TRVs/pumps on this system.
Where to start?
First an admission: I'm inclined to overcomplicate things. Hopefully the combined brains of DIYnot will help me identify the simpler solutions.
Second: I apologise for the length of this post.
Background: Old house "YH" had Rayburn powering a gravity hot water system and a pumped radiator system. At some point an LPG boiler was added as a backup. Rayburn was undersized for old farmhouse so we tried to improve, however, a dodgy "Green" company installed undersized biomass furnace and heat store system and then went bust. Subsequently had to (re)install backup LPG boiler, to help with cold spells and being away from home etc.
I've also made some improvements to increase efficiency (bypass valve so we're not sending 70m of 4°c water through the radiators waiting for the hot water to arrive). But each of these systems has been partly appended to the previous system, such that we now have a non-standard system that upsets the local plumbers.
However, apart from being undersized, it has worked well for over 10 years (I've replaced odd parts here and there).
I need help with 2 issues that are different, but possibly one will affect the other, so I'm putting both here.
The second issue:
I can't afford to replace the biomass system with a correctly (larger) sized one. So I'm looking to improve efficiencies wherever I can. I now think I need to look at smart TRVs so we're not trying to heat the whole (very un-insulated) house because one room is cold.
The "easy" bit is to put in a smart circulation pump and TRVs that will work with the LPG boiler in the house.
The complicated bit is that the heat store is 70m away (and 5.5m below) the house circulation pump, so it has two pumps, one in the house and one by the heat store to bring (and return) the heat store water to the house system. I think these two pumps would need adjust their flow rates to match the house pump? How can these pumps speeds be adjusted together?
My overcomplicating mind sees a Home Automation solution with a central software program monitoring the hot water needs and sending the required speed control signals to each of the three pumps as required.
I think I can do this, but it makes the system reliant on the software which makes it inherently more complicated for future plumbers dealing with issues/repairs etc. And, software itself isn't always reliable anyway!
Is there any way to redesign the whole system to simplify these complications?
The primary issue:
When we fired up the biomass system last autumn - it isn't working properly.
When called for, the heat store pumps (P2 & P3) turn on and hot water arrives in the house system, however, the upstairs radiators get warm-ish, but the downstairs radiators stay cold - I know, a common problem with plenty of advice already available - However, all the radiators get hot when the LPG boiler is the heat source. So many of the usual suspects cannot apply here.
I've been through the whole system (and replaced various aging components) nothing has fixed this problem.
I can only imagine it's some kind of restriction in the flow from the heat store, but I'm not sure where/how that could be.
I suspect the pumps the dodgy biomass company installed didn't adequately allow for the friction loss of the pipe run, but they've just about managed it for the last 10 years. Now something is making that harder and it can't get enough flow.
I've tried to work out the required flows, but the pump and boiler companies just want to know what the existing pumps are (even if they're undersized) or to be given the correct specifications by the installer (various including dodgy and bust). The LPG boiler company won't tell me what the maximum and minimum flows are required for their boiler, so I don't know if any of the pumps are in the right range at all.
I'd love to find a local plumber/engineer to help with my Frankenstein's monster of a system, but I live in very rural mid Wales and haven't found a suitable person yet (please message me if you are this person!).
Information and things I have tried:
Please see attached pictures.
When the LPG boiler is going, the boiler overheats if Pump 1 (UPS 3 15-50/65) is on Constant Curve 1. CC 2 or 3 are fine, so the flow rate in the house system needs to be something above 1 m³/h.
2 - 2.5 m³/h seem to work well.
The biomass ultrasonic flow meter reading varies between 0.3 - 0.4 m³/h when it's going through the bypass valve. It drops to around 0.1 - 0.3 m³/h once the bypass valve closes and Pump 1 joins in to push it round the house.
All of these are too slow.
I've checked (and sometimes replaced) every pump, motorised valve, gate valve etc.
No repairs or replacements have made any difference.
I've bled the radiators (no air) and tried to identify where any other airlocks could be (I can't find any). There's no sign of sludge and very little debris in the Fernox TF1 filter or anywhere else in the system.
There are drain points at the lowest point in the cellar (~7.5m head from F&E tank). I've timed how long it takes to fill a 2 litre jug, without any pumps on, to check for obstructions in the pipes between the heat store and the heating system in the house (although I'm not sure where the obstruction would be):
The quickest (F&E tank > cellar drain ~30m) around 4 seconds.
The longest (F&E tank > heat store > cellar drain ~100m) around 30 seconds.
The timings are similar with the water flowing in either direction (normal flow direction or reversed).
I don't know if that tells me much more than the longer the pipe run, the lower the pressure?
The most curious question for me is what has changed? The system worked well enough for the last 10 years. Now suddenly it doesn't work although there's no clear fault with any individual part of the system.
Problems to solve:
What should the flow rate be for the LPG boiler?
What flow rate should the biomass pumps be supplying at the house?
Why aren't they? Or what is stopping them?
Once the biomass system is working again, what's the best way to upgrade the existing system to smart TRVs and pumps to allow for varying flow rates? Allowing for the long pipe runs, and 3 different pumps in 2 different locations.
Or, is there a completely different system design that would solve all the issues?
I again reiterate that I'd love to find someone local who can work with me on this, but failing that - You are my only hope!
Please help!
