Frustrating radiators not heating up altogether

[Homerlu]

I would appreciate any help that anyone can give before we spend any more money on diagnosing this problem...when the radiators are on upstairs the ones downstairs go off. When we turn off the rads upstairs the ones downstairs heat up. Not to scorching - but fairly hot. At all times the flow pipes are very hot and return pipes are hardly warm. We have had a heating engineer round and he has put in some system cleaner which made no difference at all. He has checked a couple of pipes - there are plastic pipes connected to the original copper ones and checked them and although there was some resistance -which could have been some water left in the system - it wasn't definitely clear that there was a blockage. The mains ones from the boiler are under a chipboard floor so wold have to get the whole floor up to have a further look. He tried cleaning the exposed bit out a bit and when the system was put back together there was absolutely no difference and we still have to turn off upstairs before the downstairs comes on. He says that the pump is working in the glowworm boiler and the boiler seems to be working. He has advised that its def a blockage in the plastic pipework as its a typical problem of plastic pipes and its best to fit a new complete heating system and boiler which we cannot afford. Anyone got anything else we can try before we go down this route?

 

[TheVictorian]

Sounds like the system just needs balancing, has your heating guy done this?

 

[Homerlu]

No - i asked him to do this and he said its not worth it as the water is not flowing round properly

 

[bolshy]

What type of boiler? Do you have a hot water cylinder? How do you know your pump is working? Does the flow and return get hot when the upstairs rads are on? Are there any zone valves? More info please....

 

[Homerlu]

Its a gloworm ultracom cxi. The hot water is working fine. The heating guy said the pump was working, although he didnt get it off. When he turned the speeds to slow and fast it responded and you can hear the water going round when its on. As we haveinherited the heating system and boiler we were not sure whether there are zone valves - but as its quite a simple layout - 3 rads and a towel heater upstairs and 3 rads downstairs - and all pipework downstairs is exposed and thenpipework we did expose upstairs didnt have any zone valves, it only leaves pipework in one room to the boiler which we would have to get floor up to check. This is the plastic pipework area which i said about.
The towel heater and the rad next to the boiler get scorching hot in seconds. I have tried balancing these - but it makes no difference to the other rads, and they stay extremely hot.

 

[bolshy]

Well, if you're sure that the pump is working and there are no zone valve issues then it can only really be partially blocked pipework or a very bad system balance. Cleaning/descaling chemicals aren't likely to shift old hardened deposits unless used in conjunction with a powerflush machine. Unless you can see all of the pipework causing the problem, you won't know if there's anything else causing a problem ie. undersized pipework or a hidden manual bypass for instance. I take it all radiators are piped with a flow and return? Wouldn't be the first time I've seen a system where a mixture of single and double piped rads have been used. Some systems I've seen have had rads piped up in series too.
My advice would be to have another careful balance of the system after shutting off the ones which get hot straight away.

 

[Whitespirit66]

Has the system worked properly before? What size are the rads?

Doesn't sound like a very big system, shouldn't really be taxing your boiler too much. As the system currently favours the upstairs rads, maybe pointing to balancing, or poss pump.

 

[Homerlu]

Thanks very much Bolshy - will give it a go over the weekend again. Out of interest would you suggest that we change the pump and put in a filter (as apparently it doesnt have one) before we go down the road of changing / breaking the floor up to get to the pipework?

 

[Homerlu]

The system has worked properly before - but not to what I would think the full capacity - but i really do think that was down to balancing after having read about balancing now. We have had hot and warm rads but they have all come on at once - except when the rad closest to the boiler is on then the kitchen (the rad at the end of the circuit) is cool. So we leave that 1st rad off. Downstairs there are 2 single 1.4m rads and one double 1.2 and upstairs there are 3 x 1.2 singles and a towel rail

 

[Whitespirit66]

Confusing one. Could be weak pump, balancing, undersized flow and return pipes or partial blockage, especially if any microbore pipe is involved. Or poss a combination of several.

Without seeing the situation, not easy to fathom.

 

[bolshy]

When you say filter, you mean Magnaclean or something similar? Did the heating engineer add any chemicals to the circuit to attempt to help clean it? Was it ever dosed with inhibitor? If you are fitting a filter then get some sludge remover/descaler and add that too - see what you manage to collect in your new magnetic filter. A careful balance could solve your problems, but hardened deposits in an untreated system can cause big problems after only a year or so. Your heating circuit hot water will always try to find the easiest route back to the boiler. I wouldn't rip up any flooring or change any components yet. Good luck.

 

[Homerlu]

Thanks so much for your advice guys. We will have a go at balancing over the weekend and keep u posted. I see ur in bristol Whitespirit66 if you would have a look for us please let me know.