New boiler fitted, heating isn't as warm as before
Discussion
Hi,
We've just had a new condensing boiler fitted to replace our very old Potterton Flamingo. It's not a combi boiler, just a regular open vented jobby as a direct replacement for our old one. I appreciate it’s a lot colder now than it was a month ago when our boiler was turned off, but it doesn’t seem to be heating the house as well as our old one. The hot water is hot and to be honest I don’t know if it is are any hotter or cooler than it was before, but the radiators don’t seem to be very hot and they don’t stay warm for very long. They’ll start getting warm then get cool shortly afterwards. I have the heating dial on the boiler turned all the way up to high which I think is 75 or 85 degrees off the top of my head which doesn’t seem right to me. I also have the room thermostat turned up quite high, around 25 degrees.
Any ideas? Is it just that it’s not as powerful as my old boiler?
We've just had a new condensing boiler fitted to replace our very old Potterton Flamingo. It's not a combi boiler, just a regular open vented jobby as a direct replacement for our old one. I appreciate it’s a lot colder now than it was a month ago when our boiler was turned off, but it doesn’t seem to be heating the house as well as our old one. The hot water is hot and to be honest I don’t know if it is are any hotter or cooler than it was before, but the radiators don’t seem to be very hot and they don’t stay warm for very long. They’ll start getting warm then get cool shortly afterwards. I have the heating dial on the boiler turned all the way up to high which I think is 75 or 85 degrees off the top of my head which doesn’t seem right to me. I also have the room thermostat turned up quite high, around 25 degrees.
Any ideas? Is it just that it’s not as powerful as my old boiler?
Its possible that the radiators have not been balanced properly. You will probably have a thermostatic valve on one side and an outlet valve on the other side with a blank cap on it. The radiator needs to be balanced to ensure that the water is not flowing too fast or too slow through the radiator so that it heats up properly.
Get the fitter in to take a look at the balancing. They also should have performed a full system flush prior to fitting the new boiler to clean out any crap in the system and added corrosion inhibitor afterward.
Finally, if you don't have thermostatic radiator valves, get some fitted. Pay back is less than two years IIRC.
Get the fitter in to take a look at the balancing. They also should have performed a full system flush prior to fitting the new boiler to clean out any crap in the system and added corrosion inhibitor afterward.
Finally, if you don't have thermostatic radiator valves, get some fitted. Pay back is less than two years IIRC.
douglasr said:
Its possible that the radiators have not been balanced properly. You will probably have a thermostatic valve on one side and an outlet valve on the other side with a blank cap on it. The radiator needs to be balanced to ensure that the water is not flowing too fast or too slow through the radiator so that it heats up properly.
Get the fitter in to take a look at the balancing. They also should have performed a full system flush prior to fitting the new boiler to clean out any crap in the system and added corrosion inhibitor afterward.
Finally, if you don't have thermostatic radiator valves, get some fitted. Pay back is less than two years IIRC.
I've had thermostatic valves fitted, yes. He also said he flushed the system and added corrosion inhibitor. Get the fitter in to take a look at the balancing. They also should have performed a full system flush prior to fitting the new boiler to clean out any crap in the system and added corrosion inhibitor afterward.
Finally, if you don't have thermostatic radiator valves, get some fitted. Pay back is less than two years IIRC.
danyeates said:
I think it’s a lower rating than the old one,
Mystery partially solved.The output of the boiler is [in this simple case] irrelevant to it's efficiency. Your old boiler may have had a 20kW output but be 50% efficient. A new boiler may still have a 20kW but be 80% efficient thus saving you money by using less fuel.
Unless the previous boiler was vastly over spec'd (in output terms) then fitting a boiler of lesser output seems a bit odd. It will, for a start, result in the 'slower' heat up you experence.
A 15kW may well be 'sufficient' for you needs though, ie - heating your house and providing hot water.
For others who maybe in the position of changing their boilers soon then make sure you're either getting a new boiler with the same output or if it is of lesser output then ask what the effect of this is going to be on your home.
I'd still check the rads for cold spots as they could be blocked / need bleeding too.
ETA: clarified a paragraph about boiler size.
Edited by mk1fan on Tuesday 16th November 15:23
danyeates said:
Hi,
We've just had a new condensing boiler fitted to replace our very old Potterton Flamingo. It's not a combi boiler, just a regular open vented jobby as a direct replacement for our old one. I appreciate it’s a lot colder now than it was a month ago when our boiler was turned off, but it doesn’t seem to be heating the house as well as our old one. The hot water is hot and to be honest I don’t know if it is are any hotter or cooler than it was before, but the radiators don’t seem to be very hot and they don’t stay warm for very long. They’ll start getting warm then get cool shortly afterwards. I have the heating dial on the boiler turned all the way up to high which I think is 75 or 85 degrees off the top of my head which doesn’t seem right to me. I also have the room thermostat turned up quite high, around 25 degrees.
Any ideas? Is it just that it’s not as powerful as my old boiler?
One possibility is the boiler is wired incorrectly. There will be a Thermostat on your hot water tank - when it reaches temperature it should shut off the flow of water to the tank only but if the wiring is wrong it might be closing the whole system down.We've just had a new condensing boiler fitted to replace our very old Potterton Flamingo. It's not a combi boiler, just a regular open vented jobby as a direct replacement for our old one. I appreciate it’s a lot colder now than it was a month ago when our boiler was turned off, but it doesn’t seem to be heating the house as well as our old one. The hot water is hot and to be honest I don’t know if it is are any hotter or cooler than it was before, but the radiators don’t seem to be very hot and they don’t stay warm for very long. They’ll start getting warm then get cool shortly afterwards. I have the heating dial on the boiler turned all the way up to high which I think is 75 or 85 degrees off the top of my head which doesn’t seem right to me. I also have the room thermostat turned up quite high, around 25 degrees.
Any ideas? Is it just that it’s not as powerful as my old boiler?
I've got a new 30KW (Gloworm) boiler in a 4 bed detached & its more than big enough so I doubt the 15KW boiler is your problem.
Check your header tank in the loft to make sure its got water in it - had a plumber here once who did some work & forgot to switch the water supply to th eheader tank back on, was nearly empty when I discovered it & if it runs dry the boiler will shut off.
The room stat must be working or the rads wouldn't get warm at all.
Make sure you bleed the radiators
If your radiators don't have thermostatic valves then you may need to balance them.
Start by opening them all fully (valves at both ends) and then find which one(s) gets hotest & start closing those ones down a bit till the other start heating up properly.
If you do have thermostatic valves you can still need to balance the system although its not as important because when a room heats up the radiator will shut off thereby forcing water to other parts of the system. It kind of self balances. There is also the point that if you have Tstats on the rads and leave the other end fully open you get maximum flow & maximum heat as quickly as possible when the stat does open.
On the other hand it can cause the T'stat valve to chatter a bit as it opens so if that's happening if you reduce the flow at the other end of the radiator it can make the system run a bit quieter.
Lastly if you have Tstat valves, take the heads off & make sure they are not stuck shut. There is just a pin under the head about 3mm long on mine, you should be able to push it up & down with something blunt & metal (side of an adjustable spanner etc). If its stuck down spray a little WD40 on it & wait a few minutes it should start to come up. If not you may neeed to loosen the nut around it.
danyeates said:
I appreciate it’s a lot colder now than it was a month ago when our boiler was turned off,
Where you in the house last winter? It could just be the temp drop - our house has struggled to keep warm for the last few days.15KW should be plenty for a 2 bed terrace unless it's of massive proportions or is very poorly insulated, especially once the hot water is hot and it's only doing the heating.
Is the boiler getting to max temp and then cutting out and relighting again (ie cycling at the boiler stat setting)?
The radiators may be cooling quicker as the pump probably runs on now after the boiler has been turned off so the system dissipates its residual heat pretty quickly, again, especially in cold weather.
Right, thanks for both of your replies, again, I will read in more depth when I get home and have the boiler and radiators in front of me.
The gas engineer fitted new thermostatic valves in most of the rooms and a new room thermostat in the lounge (didn't even know he was doing that!) so I assume he balanced and bled the radiators properly.
The gas engineer fitted new thermostatic valves in most of the rooms and a new room thermostat in the lounge (didn't even know he was doing that!) so I assume he balanced and bled the radiators properly.
danyeates said:
Right, thanks for both of your replies, again, I will read in more depth when I get home and have the boiler and radiators in front of me.
The gas engineer fitted new thermostatic valves in most of the rooms and a new room thermostat in the lounge (didn't even know he was doing that!) so I assume he balanced and bled the radiators properly.
The room T'stat in the lounge will over ride everything. Some would say its a bit pointless if you have Stats on all the radiators as well (which is why I don't have one at all). The gas engineer fitted new thermostatic valves in most of the rooms and a new room thermostat in the lounge (didn't even know he was doing that!) so I assume he balanced and bled the radiators properly.
Suggest crank that up to the max to start with & set the TRV's at a sensible level for each room & see what happens - it might be that its just the Room Stat over-riding everything.
Do you know if a By-Pass has been installed in the heating pipework?
It should be an automatic item fitted on the flow after the pump but before the zone valves and connecting into the return. If they are not set up properly it allows water to flow freely around flow and return from the boiler, meaning not as much heat can flow to the rads.
It should be an automatic item fitted on the flow after the pump but before the zone valves and connecting into the return. If they are not set up properly it allows water to flow freely around flow and return from the boiler, meaning not as much heat can flow to the rads.
Iain328 said:
The room T'stat in the lounge will over ride everything. Some would say its a bit pointless if you have Stats on all the radiators as well (which is why I don't have one at all).
The system runs less efficiently without a room thermostat. Plumbers often don't fit them because they can't be arsed to set the system up correctly. Without one you are using the boiler thermostat to control the heating by means of cycling on the flow and return. Part 'L' of the building regulations means that you CANNOT fit a new boiler without a room thermostat. (Not if you want the system signed off anyway.)Ferg said:
Iain328 said:
The room T'stat in the lounge will over ride everything. Some would say its a bit pointless if you have Stats on all the radiators as well (which is why I don't have one at all).
The system runs less efficiently without a room thermostat. Plumbers often don't fit them because they can't be arsed to set the system up correctly. Without one you are using the boiler thermostat to control the heating by means of cycling on the flow and return. Part 'L' of the building regulations means that you CANNOT fit a new boiler without a room thermostat. (Not if you want the system signed off anyway.)Appreciate this is your line of work so could you explain why its not good to let the boiler T'stat do the work & also the significance of the "part L" sign off?
Iain328 said:
Appreciate this is your line of work so could you explain why its not good to let the boiler T'stat do the work & also the significance of the "part L" sign off?
The boiler will run unnecessarily to heat up the flow and return and bypass circuit until the boiler thermostat turns it off. If the system is correctly balanced the Room Thermostat won't turn the boiler off when the rest of the system needs heat. It's important to put the Room Thermostat in the space with most air changes, too, but they do tend to end up in rooms with secondary heating.Anything requiring Building control sign off will be checked when the house is sold. Heating systems which have had new boilers fitted have required a Benchmark certificate for 7 or 8 years. This document includes a Part 'L' efficiency check-list which must be completed by the installer and signed-off with their Gas Safe number.
mk1fan said:
danyeates said:
I think it’s a lower rating than the old one,
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