Heating driving me mad

[Mikefearn83]

Hi.

We have an open system in our house, 28kw boiler and 15 rads of various sizes. House is quite large and old.

We've never been able to get the heating running really well to be honest but most things have been changed like rads, pump, 3 port value.

I've had the system balanced twice in the last few years and both times all rads were boiling hot and seemed to be working well. This lasts a couple of days and then things start to cool off again with most rads getting warm/hot(ish) but nowhere near straight after balancing. The water leaving the boiler and the 3 port value is boiling hot but the rad are unfortunately not. The neighbour is a boiler engineer and did the second balance for me, he mentioned about maybe changing it to a pressurised system but given the age of some pipework stated it might be more problematic.

We have a Grundfos UPS3 and doesn't make a difference between speed 2 and 3 Constant Curve.. I know this pump has a couple of additional options being proportional pressure and constant pressure. Constant pressure I believe is for underfloor heating and proportional mode just seems to stop the pump working at all.

Anyone got any ideas for me please.

Thank you. Mike.

 

[gas112]

3 port ? with 15 rads going to struggle pretty restricted should be two two ports

 

[Mikefearn83]

3 port ? with 15 rads going to struggle pretty restricted should be two two ports

What do you mean exactly. Thanks.

 

[dilalio]

What do you mean exactly. Thanks.

S plan.
Not Y Plan.
It's just better.

 

[gas112]

What do you mean exactly. Thanks.

simple the valve is too restrictive

 

[stem]

I've had the system balanced twice in the last few years and both times all rads were boiling hot and seemed to be working well.

It works sometimes, so to me that would suggest the valve can let enough water through to heat the rads. Unless I've missed something.

 

[dilalio]

We've never been able to get the heating running really well to be honest

all rads were boiling hot and seemed to be working well

??

 

[Notch7]

I've had the system balanced twice in the last few years and both times all rads were boiling hot and seemed to be working well. This lasts a couple of days and then things start to cool off again with most rads getting warm/hot(ish) but nowhere near straight after balancing. The water leaving the boiler and the 3 port value is boiling hot but the rad are unfortunately not. The neighbour is a boiler engineer and did the second balance for me, he mentioned about maybe changing it to a pressurised system but given the age of some pipework stated it might be more problematic.

have you always had this problem or has it got worse over time?

do the ground floor rads take feed from drops upstairs?

do you find upstairs better than downstairs or visa versa etc?

Does the system suffer from air, do you have to bleed the radiators frequently?

I understand from professional plumbers that traditional open vented systems can actually work very well and keep the water quite clean if the system works well, but if you are getting air in and youve got sludge, things might not be too great

 

[Notch7]

We've never been able to get the heating running really well to be honest but most things have been changed like rads, pump, 3 port value.

So all the radiators are new?

have you ever have a power flush or even just a mains flush?

 

[Mikefearn83]

Most rads have now been changed but a few old ones remain.

Upstairs seem to heat better than down.

I believe there are drops to the downstairs rads.

The system was working very well after a full balance with all rads boiling hot. But as stated, it only takes a couple of days for things to change and then everything just doesn’t seem to get as hot anymore.

No problems with air, rads all bled and air doesn’t seem to return.

Never had power flush but system has been cleaned, drained and refilled.

 

[Johntheo5]

Suggest you get one of those plug in energy monitors, plug it into a independent trailing socket or whatever and plug the UPS3 cable into the energy monitor, you can then read off the power in watts (W) and the flowrate can then be easily read off from the UPS3 pump curves, that will tell a lot.

 

[Notch7]

Most rads have now been changed but a few old ones remain.

Upstairs seem to heat better than down.

I believe there are drops to the downstairs rads.

The system was working very well after a full balance with all rads boiling hot. But as stated, it only takes a couple of days for things to change and then everything just doesn’t seem to get as hot anymore.

No problems with air, rads all bled and air doesn’t seem to return.

Never had power flush but system has been cleaned, drained and refilled.

if youve always struggled to get decent heat then gas112, who is a very experience plumber / heat engineer has likely identified a most likely design fault in your system:

simple the valve is too restrictive

I presume its not microbore?

if its conventional 22mm and 15mm then you should get enough flow, but it is quite an old system and it might have sludge in it -it can be hard to force the water to go down stairs to the radiators at each drop, I had the same problem until I had the system changed to a new boiler pressurised / sealed