Problem with Glow-worm Ultracom 38Cxi, possibly....

[shaunos]

We had the above installed last February, and it was working fine until May. Since then it's only been serving hot water, as it's been warm(ish).

Over the summer we've done some fairly major building works, which has involved removing/changing the upstairs radiators, and adding in 3 additional ones.

So, yesterday with it getting a bit cold again, I went round and slowly filled up/bled the radiators. No leeks (a result ....but...

When turning the system back on, it all fires up, goes up to 70c, and the rads warm up, infact they get hot. But after about 20 minutes, the boiler keeps on clicking off. You can see, it turns on the CH, you watch the guage go upto 71c, then it just turns off, back to the std pressure display (which is at 1.3bar if it's relevant). It then does this constantly.

I've been round and checked all the rads again, and while most are hot, some are not great. I've also noticed the Return pipe into the boiler is very hot, and also some of the rads only seem to be hot on one side.

I can't get hold of my plumber at the moment, so I'm looking for ideas, as I've reached the limit of my knowledge.

All rads have TRV's. The boiler has an external Room Stat, but I've removed it as a test, and the same thing happens.

HW is working fine.


Any clues would be great......

Thanks...

 

[spacethegas]

it sounds like your radiators need balancing.

look here.

http://www.diydata.com/projects/centralheating/balancing/radiator_balancing.php

 

[twgas]

would agree with balancing

what have you done with the wires from the r/stat.....if you left them disconned the heating shouldnt work, if you bridged them the boiler would only operate on its own stat as long as the CH was on at the prog, which would give the symptoms you described earlier

 

[Deleted member 105431]

how many rads have you got? Has the boiler been range rated for the heating? One rad should have no trv (pref rad nearest to roomstat or bathroom rad) as the boiler internal bypass is inadequate, check the balancing of the system and pump speed. If all else fails the boiler should be under warranty so call glow worm 01773 8282100

 

[shaunos]

how many rads have you got? Has the boiler been range rated for the heating? One rad should have no trv (pref rad nearest to roomstat or bathroom rad) as the boiler internal bypass is inadequate, check the balancing of the system and pump speed. If all else fails the boiler should be under warranty so call glow worm 01773 8282100

Hi,

We have 18 rads on the system now....

Range rated? Not sure what that means? It was all working perfectly in May.

Why should one have no TRV? I've left the one in the upstairs bathroom on max though,

Room stat is wireless. It's not that, I know how to wire the boiler without it, and it showed the same symptons.

I'm just not convinced it's the boiler yet, as we have been doing work/replacing things.

Thanks guys....

 

[mrking]

you have air trapped in the system and you are not getting full circulation.

 

[shaunos]

you have air trapped in the system and you are not getting full circulation.

I would agree with you....but it's not in the rads...all bleed water as soon as you touch the bleed valves...

How do I fix it?

 

[snb]

have you checked that the bleed cap on the pump is open? Pump could be air locked. Other wise whilst the boiler is on heating add more pressure to the circuit.

 

[shaunos]

have you checked that the bleed cap on the pump is open? Pump could be air locked. Other wise whilst the boiler is on heating add more pressure to the circuit.

Not sure how to check a bleed cap, don't know what it is!!

What's a safe max pressure to take the system up to? What should it be at?

 

[GPlumb]

Make sure the automatic air valve in the boiler is open (check the instructions), to bleed them pump unscrew the big silver screw in the middle until some water comes out.

Do this when boiler is cold.

 

[shaunos]

No air in the pump by the looks of it. It says the air bleed valve is automatic...

 

[mrking]

You said that you altered/added some radiators. What did you do exacty and was it done by a plumber/heating engineer?[/u]

 

[shaunos]

You said that you altered/added some radiators. What did you do exacty and was it done by a plumber/heating engineer?[/u]

Replaced 3 of them..direct replacement, just new valves.

Added 3, took a "T" from the nearest flow/return point.