Radiator auto bleeders and thermostatic valves
Discussion
It's getting to that time of year when we might have to consider cranking the boiler back into life.
I've been meaning to fit some thermostatic valves to the radiators for a while now. Tool staion have an offering for £6.25 each which look fine to me but I also notice they offer a slightly more expensive 'dual flow' one. Does it matter which one I go for? All rads are horizontal mount.
I also noticed that they have auto air venters that replace the bleed plug on the radiator. Are these any good? I could see them making the job of refilling the system a much easier process but I don't want to waste my money if they don't work.
Thanks in advance.
I've been meaning to fit some thermostatic valves to the radiators for a while now. Tool staion have an offering for £6.25 each which look fine to me but I also notice they offer a slightly more expensive 'dual flow' one. Does it matter which one I go for? All rads are horizontal mount.
I also noticed that they have auto air venters that replace the bleed plug on the radiator. Are these any good? I could see them making the job of refilling the system a much easier process but I don't want to waste my money if they don't work.
Thanks in advance.
Dual flow TRVs can be fitted either end of the radiator, instead of just on the flow side.
Tbh I don't like cheap TRVs - I find them to be unreliable and prone to failing/sticking. But then I guess I only get called out to failed ones anyway, so my experience of them may not be entirely neutral
If you're going to the trouble of fitting TRVs throughout the house then it's worth giving the system a clean out first. Add in some chemical cleaner such as Sentinel X400 and leave it in for 1-4 weeks (depending on the state of your system) with the heating operating to give it time to work. You can then combine flushing it out with draining down to fit the valves.
It's also worth replacing the lockshield valves at the same time as they're not expensive.
Unless your boiler has a bypass valve fitted, leave at least one radiator without a TRV to allow a path for water to circulate if all the TRVs close off. Not doing so will put undue strain on the pump.
When you refill, make sure you add in corrosion inhibitor, such as X100.
I don't really see the point in automatic bleed valves. There shouldn't be any need to regularly bleed radiators if the system is in good condition and you have inhibitor in it.
Tbh I don't like cheap TRVs - I find them to be unreliable and prone to failing/sticking. But then I guess I only get called out to failed ones anyway, so my experience of them may not be entirely neutral
If you're going to the trouble of fitting TRVs throughout the house then it's worth giving the system a clean out first. Add in some chemical cleaner such as Sentinel X400 and leave it in for 1-4 weeks (depending on the state of your system) with the heating operating to give it time to work. You can then combine flushing it out with draining down to fit the valves.
It's also worth replacing the lockshield valves at the same time as they're not expensive.
Unless your boiler has a bypass valve fitted, leave at least one radiator without a TRV to allow a path for water to circulate if all the TRVs close off. Not doing so will put undue strain on the pump.
When you refill, make sure you add in corrosion inhibitor, such as X100.
I don't really see the point in automatic bleed valves. There shouldn't be any need to regularly bleed radiators if the system is in good condition and you have inhibitor in it.
jagnet said:
Dual flow TRVs can be fitted either end of the radiator, instead of just on the flow side.
Tbh I don't like cheap TRVs - I find them to be unreliable and prone to failing/sticking. But then I guess I only get called out to failed ones anyway, so my experience of them may not be entirely neutral
If you're going to the trouble of fitting TRVs throughout the house then it's worth giving the system a clean out first. Add in some chemical cleaner such as Sentinel X400 and leave it in for 1-4 weeks (depending on the state of your system) with the heating operating to give it time to work. You can then combine flushing it out with draining down to fit the valves.
It's also worth replacing the lockshield valves at the same time as they're not expensive.
Unless your boiler has a bypass valve fitted, leave at least one radiator without a TRV to allow a path for water to circulate if all the TRVs close off. Not doing so will put undue strain on the pump.
When you refill, make sure you add in corrosion inhibitor, such as X100.
I don't really see the point in automatic bleed valves. There shouldn't be any need to regularly bleed radiators if the system is in good condition and you have inhibitor in it.
Wonderful thanks. Hadn't really considered the need to leave one rad without a valve but that sounds like a good idea to me. Will take onboard everything else you've mentioned.Tbh I don't like cheap TRVs - I find them to be unreliable and prone to failing/sticking. But then I guess I only get called out to failed ones anyway, so my experience of them may not be entirely neutral
If you're going to the trouble of fitting TRVs throughout the house then it's worth giving the system a clean out first. Add in some chemical cleaner such as Sentinel X400 and leave it in for 1-4 weeks (depending on the state of your system) with the heating operating to give it time to work. You can then combine flushing it out with draining down to fit the valves.
It's also worth replacing the lockshield valves at the same time as they're not expensive.
Unless your boiler has a bypass valve fitted, leave at least one radiator without a TRV to allow a path for water to circulate if all the TRVs close off. Not doing so will put undue strain on the pump.
When you refill, make sure you add in corrosion inhibitor, such as X100.
I don't really see the point in automatic bleed valves. There shouldn't be any need to regularly bleed radiators if the system is in good condition and you have inhibitor in it.
Depending on the system, you should really ensure that there is a differential bypass valve fitted. Some boilers contain one and any 'Y-plan' system (with a mid-position valve) will not require one. Having one radiator always open for the pump over-run is often not enough for bi-directional radiator valves. The manufacturers (in common with boiler manufacturers) do stipulate a minimum percentage of the system as a bypass. If you are going to the trouble of changing valves, I would switch the heating on from cold and mark the flow on all the radiators for fitting TRVs.
OP, I have an automatic bleed valve fitted to one of my rads. It's the nearest one to my central heating pump. My plumber recommended it and fitted it for me. Since fitting, I have never had to bleed the system, so it's been good.
When funds permit I am going to get my system power flushed as I think the rads have a bit of muck in them...my system has inhibitor in it, just think it suffered years of neglect at the hands of the previous owner.
When funds permit I am going to get my system power flushed as I think the rads have a bit of muck in them...my system has inhibitor in it, just think it suffered years of neglect at the hands of the previous owner.
Cheers all. Decided against the auto bleeders in the end.
I have my valves though. They're single direction ones so I will need to fit them on the flow side. I assume if I leave one out in this configuration I should be fairly safe?
I'm currently draining the system, but I cannot believe how long it is taking. It's a five radiator flat with a combi boiler. I have the fill loop closed and all radiator valves are open and bleed screws loosened. I have a hose attached to the outlet. It is draining water slowly but I would say it's bee going for nearly two hours now. Is this normal or have I spazzed up somewhere?
I have my valves though. They're single direction ones so I will need to fit them on the flow side. I assume if I leave one out in this configuration I should be fairly safe?
I'm currently draining the system, but I cannot believe how long it is taking. It's a five radiator flat with a combi boiler. I have the fill loop closed and all radiator valves are open and bleed screws loosened. I have a hose attached to the outlet. It is draining water slowly but I would say it's bee going for nearly two hours now. Is this normal or have I spazzed up somewhere?
If you fit 'single flow' TRV's to the wrong end of the rad it makes a strange noise so you have to fit it to the other end (been there, done that)
Top-notch stuff like Honeywell doesn't care which direction the flow is.
Had a mix of builder's merchant own brand and better stuff (in a sale, no expense spared) on the system. Own brand stuff all expired long ago - better stuff still going strong. There doesn't seem to be any standardisation between brands so if you change brands you will probably have to shorten/lengthen the pipe.
Moral: don't buy cheap.
Top-notch stuff like Honeywell doesn't care which direction the flow is.
Had a mix of builder's merchant own brand and better stuff (in a sale, no expense spared) on the system. Own brand stuff all expired long ago - better stuff still going strong. There doesn't seem to be any standardisation between brands so if you change brands you will probably have to shorten/lengthen the pipe.
Moral: don't buy cheap.
Gad-Westy said:
It is draining water slowly but I would say it's been going for nearly two hours now. Is this normal or have I spazzed up somewhere?
I had a similar issue recently and on quizzing a plumber I was told I might have a blocked fill pipe (pipe from header tank the feeds cold water into the system - assuming an open vented system) - I was trying to flush with 1 rad totally disconnected. I ended up cutting the pipe and clearing the blockage (the T joint had filled with crud) and it was fine after that. Try tapping GENTLY with a hammer, various bits of pipework to see if any potential blockages are present.Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff