Heating issue after installing TRVs

Kealyboy

Hi I have replaced old rad valves with TRV. I drained down the heating system (open vented heating system). Fitted TRVs refilled heating system. Vented all rads, down stairs first then up stairs. There was also a vent on the flow pipe at boiler vented that too. Turned back on heating and there was a bit of noise of gurgling water air in system. Boiler cycled off after a couple of mins on temp. Now most of the flow pipes going to rads are red hot and returns are cold. Rads are not heating up obviously. I presume the system (return) is air locked now.

Anywhere I can bleed air from has being bleed. How do rectify this problem?

Thanks

Wearb

Are you getting water from all bleeds now?
Did you bleed circ pump?
Have you trv's in correct way round. Some are multi directional so doesn't matter.
Have you them all turned on full?
Try system with say all rads off except 2 to see what happens.

jimf

try bleeding the pump first as wearb suggested

Kealyboy

Wearb wrote: »

Are you getting water from all bleeds now?
Did you bleed circ pump?
Have you trv's in correct way round. Some are multi directional so doesn't matter.
Have you them all turned on full?
Try system with say all rads off except 2 to see what happens.

Yes TRVs are the right way round and yes I have bleed the pump there just after I posted the last post, no air came out of the pump just water. Yes I I had them all turned on full. Now I did as suggested, I turn off all bar one and now that one is getting hot. When that one is hot I turned on another one and then turned off the last one and so on. Individual they are all getting hot now but I can hear a lot of air being circulated and a gurgling sound.

John.G

Any idea where the vent comes off the system, it is often a continuation of the (top) inlet (flow) pipe into the cylinder, the cold feed might be teed into the cylinder return pipe or like my own you may have a combined feed and cold feed, where the cold feed is teed into the vent, these can be a PITA to vent especially when the whole system has been drained, if any zone valves were/are fitted then these should be latched open and the system then filled very slowly. You will get there eventually.

jimf

you could also crack the joint at the boiler just crack it now not undo it

Kealyboy

John.G wrote: »

Any idea where the vent comes off the system, it is often a continuation of the (top) inlet (flow) pipe into the cylinder, the cold feed might be teed into the cylinder return pipe or like my own you may have a combined feed and cold feed, where the cold feed is teed into the vent, these can be a PITA to vent especially when the whole system has been drained, if any zone valves were/are fitted then these should be latched open and the system then filled very slowly. You will get there eventually.

Yea the vent comes off the top of the flow going to the cylinder and yes it’s like your own set up, its a combined feed and expansion. I’d say I’m about 80% of the way there, still not heating up as good as before and I still can hear some air in the system. I’ll hopefully get the rest of it out tomorrow morning. What a pain in the ass this airlock is nearly taking me as long in rectifying the airlock as it took to change the rad valves lol.

Kealyboy

jimf wrote: »

you could also crack the joint at the boiler just crack it now not undo it

There was a manual bleed vent on the top of the flow pipe just before it connects to the boiler. I bleed that even though very little air came out if any. Would it be worth cracking the return joint at that point too.

jimf

Kealyboy wrote: »

There was a manual bleed vent on the top of the flow pipe just before it connects to the boiler. I bleed that even though very little air came out if any. Would it be worth cracking the return joint at that point too.

yes sometimes those vents don't work

Wearb

If there is a balance valve on the cylinder, close it off while trying to get rads working.

Are the rads you get working roasting all over, especially bottom centre?

Are you still getting only water from rad bleeds.

Kealyboy

jimf wrote: »

yes sometimes those vents don't work

Ok thanks I’ll try that tomorrow. I’ll let you know how I get on.

Thanks

Kealyboy

Wearb wrote: »

If there is a balance valve on the cylinder, close it off while trying to get rads working.

Are the rads you get working roasting all over, especially bottom centre?

Are you still getting only water from rad bleeds.

Yes I turned the balancing valve off while I turned on each road individually. I bleed a rad now and just water came out and then when I turned on the heating to just that rad I can hear a lot of air being circulated through especially hear it right down at the TRV. The rad is hot all over thought. A couple of rads the return is only getting warm while the flow is red hot.

Kealyboy

If I drain down the system tomorrow and start again is there a better way to fill the system to prevent airlocks Or am I better off sticking it out now.

Wearb

I'd remove some of the trv heads altogether, to try and get a handle on where the problem lies.

I presume you have fully opened the lock shield valves?

Is both sides of the pump getting hot?

I am not convinced it's air you are hearing, especially since you are not getting air from the rad bleeds.

I expect that there isn't a magna clean on it?

Follow each attempt to fix to it's conclusion before going to next one and you'll get there in the end.

Btw what type circ pump do you have?

Kealyboy

Wearb wrote: »

I'd remove some of the trv heads altogether, to try and get a handle on where the problem lies.

I presume you have fully opened the lock shield valves?

Is both sides of the pump getting hot?

I am not convinced it's air you are hearing, especially since you are not getting air from the rad bleeds.

I expect that there isn't a magna clean on it?

Follow each attempt to fix to it's conclusion before going to next one and you'll get there in the end.

Btw what type circ pump do you have?

It’s just an old grundfos pump see pic. No magna clean. I bleed a couple of radS there and a lot of air came out of them now at one point the air stopped and no water came out and when I closed the vent for a minute and opened it again more air came out then followed by water. I uploaded a video of down at the boiler hopefully you can make out the sound I’m hearing. Yes both sides of the pump are hot.

Kealyboy

Wearb wrote: »

I'd remove some of the trv heads altogether, to try and get a handle on where the problem lies.

I presume you have fully opened the lock shield valves?

Is both sides of the pump getting hot?

I am not convinced it's air you are hearing, especially since you are not getting air from the rad bleeds.

I expect that there isn't a magna clean on it?

Follow each attempt to fix to it's conclusion before going to next one and you'll get there in the end.

Btw what type circ pump do you have?

A few days ago I put a cleaner in the system and then flushed it out today, I removed each rad and flushed out with a garden hose before installing TRVs.

John.G

Just read all the posts there now.

You do seem to be getting a lot of air or is that noise now some form of cavitation i wonder. re alternate way of filling, I have read that some fill these systems through the drain cock on the boiler from the mains, I have a 1/2" gate valve on the filling line to the F&E tank and just crack it open when I am refilling the system from a very infrequent full drain down... just a few more questions,

Gas or oil boiler installed? (Can see with my Laptop that it is Gas)

Is the pump installed on the return to the boiler?

Was system very dirty on drain down?

Was/is the F&E tank clean?.

Is the combined vent/cold feed installed like my system below?. and was it always combined?