Nightmare of a day. Changed some rads now not heating up!

[armyash]

Hi guys

Had a pig of a job today, over at the house of a regular customer I changed 3 rads downstairs, when it came to filling up for the last time and turning the heating on, upstairs reached temperature as you would expect but downstairs only a couple of rads were getting hot and the rest were ice cold. With the pump on 3 hot water shoots out the OV pipe in to F+E but turned down to 2 this doesn't happen. But 2 may not be providing enough power to circulate properly.

Another thing, we replaced 1 rad at a time then filled up and drained down again just to try and clear the system a bit more than draining it once. When I went to fill up the first time the F+E filled but the water didn't enter the system so we was getting nothing, I turned the heating on for 30 seconds just to give the circulation a kick up the butt and it did the job.

System filled up ok but as I said only 7 out of 11 rads were getting hot. I was there for ages, at first I would get air out by stopping the pump, then starting it again, constantly bleeding the system but it got to the point where I wasn't getting any air out at all. I left it with the upstairs rads turned off and 2 of the cold rads downstairs did start warming up but very slowly.

I had to leave them with an electric heater even though the house was reaching a decent temperature, they were satisfied that I did all I could, it was getting late and they obviously wanted me gone.

What is the likely problem here?

Dodgy pump? air lock? Blockages in the system?

Some extra info: This customer regularly call us out to replace radiators as they keep developing holes and leaking everywhere. I have never known anything like it. They had the system power flushed 2 years ago but it hasn't helped.

Any info or advice you guys can give would be appreciated.

 

[Billy Bob Bob]

low head if rads are pinholeing,bungalow?

 

[armyash]

Sorry what do you mean by low head do you mean where the F+E tank is placed?


It's a house.

 

[PlumbBobBob]

sounds like an air lock to me. when you go back close all the rads upstairs to force the circulation round the rads that weren't heating, should get the air lock out then.

 

[armyash]

sounds like an air lock to me. when you go back close all the rads upstairs to force the circulation round the rads that weren't heating, should get the air lock out then.

Thanks for the reply but already tried that.

 

[Billy Bob Bob]

Sorry what do you mean by low head do you mean where the F+E tank is placed?


It's a house.

yes,if rads are constantly pin holeing you either have a low head so constantly pumping over or a pump set to high or fresh water getting in somewhere ,its a sign off oxygenation fresh water going in constantly did the water look orange?

 

[armyash]

yes,if rads are constantly pin holeing you either have a low head so constantly pumping over or a pump set to high or fresh water getting in somewhere ,its a sign off oxygenation fresh water going in constantly did the water look orange?

Yes orangey water. I searched google earlier to see about the water coming through OV and one of the results was about oxygenation.

What are possible solutions to this problem? Converting to a sealed system would be ok but what can be done to the current system?

 

[Best]

Sealed system on oil or gas is best, but can the system take a bit more pressure & can any weeps that may exist be eliminated?
If you want to stay with open vented then you could do a combined feed & vent which will prevent pumping up, but not ideal tbh.
Or you could have the pump on a negative position in relation to the feed & vent. Close coupling is one method.

 

[Reg Man]

Pump pipe work configuration incorrect, either get the open vent on the negative pressure to the pump or make it a sealed system. Could be a blocked cold feed?

 

[armyash]

Pump pipe work configuration incorrect, either get the open vent on the negative pressure to the pump or make it a sealed system. Could be a blocked cold feed?

Could be a blockage somewhere, the system did fill up but at first only the F+E filled.

 

[Kev the gas]

As above, before converting to a sealed system :-
is the boiler suitable to be on a sealed system, over heat thermostat ?
if the system has being pinholing rads in the past, be aware more leaks may well appear in the near future, may be worth replacing all rads and new rad valves.

 

[armyash]

As above, before converting to a sealed system :-
is the boiler suitable to be on a sealed system, over heat thermostat ?
if the system has being pinholing rads in the past, be aware more leaks may well appear in the near future, may be worth replacing all rads and new rad valves.

It's an old Kingfisher boiler. All rads and valves have been replaced and also taken off and flushed through.

Corrosion inhibitors

What about fitting something like this first and see if it makes a difference? I had a read up on sacrificial anodes this morning and if it is oxygenation causing the leaks this might solve that.

The more I think about it the more I think there is blockages in the system causing poor circulation.

 

[Reg Man]

Unless it is the Kingfisher MF, I do not think they had an overheat stat, so may not be suitable for sealed systems.

 

[bert large]

Sounds like an air lock. They often clear themselves after a day or so of normal use.
Failing that try draining & refilling the system, not through the F & E tank but with a hose connected to the end of one of the offending rads downstairs, filling from the bottom up & pushing the air upwards.
More often than not this method works for me when I get an air lock although I am planning to get a pipe freezer as I get so fed up with air locks on vented systems.

 

[IDCHAPPY]

This is why i hate'em :lol:

 

[stevetheplumber]

if the system is drawing air in you have to change the c/f vent configeration the fact that it didnt fill at first suggests a partially blocked cold feed if they didnt link the vent cold feed when theypowerflushed it will not have touched it

 

[armyash]

Thanks for all the replies guys. I'm sure I will be back next week so will see what happens.

 

[gassafe]

Yeah probs a partially blocked cold feed.

But if there having a series of radiators pin holing then there is an underlying problem!!! Putting new rads on & these will corrode too... You need to check the cold feed & vent configuration & ensure there no pumping over!! Pcb's need to raise the vent higher also.

The system must be in a pretty bad way with all that orange water, the boiler will rot through eventually. Putting on a sealed system could open a can of worms also!! Good luck with it!!!

 

[armyash]

Yeah probs a partially blocked cold feed.

But if there having a series of radiators pin holing then there is an underlying problem!!! Putting new rads on & these will corrode too... You need to check the cold feed & vent configuration & ensure there no pumping over!! Pcb's need to raise the vent higher also.

The system must be in a pretty bad way with all that orange water, the boiler will rot through eventually. Putting on a sealed system could open a can of worms also!! Good luck with it!!!

Thanks. Luckily whatever happens next is not my call, the boss will have to quote for extra works. I might suggest a corrosion inhibitor/sacrificial anode type thing first. The loft space is the smallest I have ever seen and there is not room for adjustment for what is there now. Will have to look at the pipe configuration also.

 

[armyash]

Was just air in the system. The customers said that it was still playing up Saturday but Sunday pretty much ok. Had to go back today and got a lot of air out of one of the upstairs rads.

All good.

Was not very happy being there until 8.30pm on Friday. I could have left earlier and told them to see if sorts itself out but I could tell that they would not have been happy, at least they saw I did all I could and were impressed by the time I left and seemed satisfied.

 

[jonnyswamp]

Nice one, now make a note of their number and never answer it again :cowboy:

 

[rpm]

I have +10 numbers listed under DNA
Do Not Answer.

 

[Reg Man]

Problem will re-occur though. unless you identify the air problem.

 

[armyash]

Problem will re-occur though. unless you identify the air problem.

They had a powerflush done by a firm a couple of years before us and they said it was after that the problems started. What I have read about oxygenation looks promising.

 

[gassafe]

I doubt the powerflush caused any problems.... They obviously requested a powerflush or needed one as the system was furred up back then too...

Theres not pipework under the ground is there? I went to one job where there was a leak under the property, the roof tank must have just kept on refilling it but the entire system was full of brown water, pipes thick with red / brownish gunk in all the pipes.

On one other job where they had had recurring pin holed rads & constant air in the system the cold feed & vent were wrong & it was gravitating over the vent, & down the cold feed, bringing a constant supply of oxygen into the system. Once that was fixed there has never been a problem with air in the rads!