Are my Grundfos pumps configured correctly? Old one pipe system, with 16 radiators powered by a 48kwh regular boiler.My bills are £800 a month.Help.

[JonnyH12]

I was just reading the manual for the two Grundfos pumps I have on the heating system, and the manual suggests using constant pressure mode for a single pipe setup.

It was previously set on constant speed 3.

My bills are currently £800 a month, so I am desperately trying to make sure everything is optmised.

I have only been in the house for a year, and the plumber that installed this system originally won't return my calls, so I've never fully gotten to grips with it.

 

[Exedon]

Size of pipework? Pictures of boiler / pumps would be useful.

 

[JonnyH12]

The boiler is in an outhouse, feeding into the cellar as shown in the third pic.

There are three grundfos pumps, one feeds the hot water tank and the other two are on the out and return valves of the pipe system.

About 10 of the 16 radiators are controlled by Honeywell TRVs.

The boiler is a Worcester Greenstar 8000, regular not combi.

I'm not sure what size the pipes are to be honest. Do you just put a mearuing tape around the main single pipe?

 

[muggles]

48kw boiler on 16 radiators? Unless the radiator in the photo is your smallest one by quite some margin, that boiler is massively oversized and likely to be a significant factor in your running costs. The primary pump isn't powerful enough to shift 48kW through that boiler's heat exchange anyway, so even if your system did need that the pump wouldn't keep up.

 

[Ltnman]

What’s the house insulation like? Seems you live in a large uninsulated drafty old house. Have you upgraded any insulation?

 

[Johntheo5]

I was just reading the manual for the two Grundfos pumps I have on the heating system, and the manual suggests using constant pressure mode for a single pipe setup.

It was previously set on constant speed 3.

My bills are currently £800 a month, so I am desperately trying to make sure everything is optmised.

I have only been in the house for a year, and the plumber that installed this system originally won't return my calls, so I've never fully gotten to grips with it.

Can you post the boiler flow and return temperatures, they ma be available from the boiler menu, if not try and measure them on the flow and return on the RH side of the low loss header.

 

[JonnyH12]

48kw boiler on 16 radiators? Unless the radiator in the photo is your smallest one by quite some margin, that boiler is massively oversized and likely to be a significant factor in your running costs. The primary pump isn't powerful enough to shift 48kW through that boiler's heat exchange anyway, so even if your system did need that the pump wouldn't keep up.

It does seem a big boiler, but I have always assumed that the installer specced it correctly. He was a specialist in one pipe systems.

Some of the radiators are a bit bigger, but some are smaller. It's a large house though, 5 bedrooms spread across two wings.

 

[JonnyH12]

Can you post the boiler flow and return temperatures, they ma be available from the boiler menu, if not try and measure them on the flow and return on the RH side of the low loss header.

I don't think I've seen this in the menu options for my boiler. To read them from the low loss header, do you mean use a thermometer on the pipes or should there be a dial? I have never removed the insulation on the llh before so it might be under that.

 

[JonnyH12]

What’s the house insulation like? Seems you live in a large uninsulated drafty old house. Have you upgraded any insulation?

Bad. The loft is fully insulated but we have single brick walls and single glazed windows. But it's listed and we can't change those things. I'm looking into indoor insulation but it's not cheap.

 

[Johntheo5]

I don't think I've seen this in the menu options for my boiler. To read them from the low loss header, do you mean use a thermometer on the pipes or should there be a dial? I have never removed the insulation on the llh before so it might be under that.

You should be able to see the flow temperature anyway, if not on the top right where the pipe enters the LLH, you can get the return from the unlagged pipe to the magnetic filter.

 

[JonnyH12]

You should be able to see the flow temperature anyway, if not on the top right where the pipe enters the LLH, you can get the return from the unlagged pipe to the magnetic filter.

Do you mean there is a temp dial behind the foam cover? I am reluctant to remove the zipties to remove it as I don't have any to replace them with. If I need too I can order some today.

The boiler is set to 73c on it's output.

 

[Johntheo5]

A thermal gun will give you a good idea off the pipework, if you have one.

 

[JonnyH12]

A thermal gun will give you a good idea off the pipework, if you have one.

I do have one. It reads at 65c just before getting to the low loss header, and around 42-46c on the return.

 

[Madrab]

Are all the radiators columns like that? What grade of listing?

 

[JonnyH12]

Are all the radiators columns like that? What grade of listing?

They are all the same style/type, large cast iron rads. But some are larger than others.

It's Grade 2. We have part of the house double glazed, but the previous owners were refused permission to do the front.