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New boiler flow and return temps

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friendlyaviator

Hi all,

Just had my new boiler installed. Went from a heat only with hot tank to a combi boiler.

Its a Ideal Logic+ 30 and in the menu it shows sensor values. I understand there should be a large difference between flow and return values but quite often when running there is only a 5 degree difference.

I'm running the central heating at 70 degrees (economy setting on the dial) but my return is often close to 70.

I have just 5 radiators, all but one is a double panel. They all heat up well but I noticed all of the lockshields are fully open. All have TRVs.

So basically I have the following questions.

1. Am I supposed to have such a small differential between flow and return.
2. How do I increase the differential
3. Should my lockshields be clouded somewhat?

Thanks in advance for your advice.

Dean
 
friendlyaviator said:
What would this involve? What shall I say to my plumber or can I rectify this myself.

Thank you.
Click to expand...

By the sounds of things, you wouldn't require 10 kW of heat.
The boiler should have been set up to allow for that amount of heat - on the heating side.
The hot water side has also to be calibrated.

To me, you situation sounds like someone has plonked it on the wall got, it going and left.
No one with any knowledge, experience or conscience would leave your combi boiler operating the way you say it is operating.

I wouldn't bother calling the Plumber back - he obviously doesn't know what he is doing.
 
You need to get confirmation that the new boiler installation has been notified to Building Control (Part L1b) this is normally via Gas Safe. This is a requirement by Law.

One of the main requirements is that the appliance & system are both installed correctly but also fully commissioned so that they work efficiently.

This, by the sounds of it, has not completed get them back.

Unfortunately it is the house holders (or landlords) responsibility to to ensure it is correctly notified.
 
The Individual who installed your boiler should have balanced the system for you and set the boiler up properly. Get him or her back to it.
Those temps are too close and if the return is that hot your new boiler is not condensing and is therefore less efficient. It is pointless having a condensing boiler that will only condense during warm up.
 
Thanks for some great replies, albeit some bad news. I have a certificate from ideal that states the boiler has been notifed to building control.

Can I get this boiler working the way it should?
Can I do it myself or do I need to call someone out?
The thermostat is wireless so I put TRVs on all rads but I can take the head off one if I need to.

Shall I contact gas safe to have the system inspected?

Dean
 
friendlyaviator said:
Thanks for some great replies, albeit some bad news. I have a certificate from ideal that states the boiler has been notifed to building control.

Can I get this boiler working the way it should?
Can I do it myself or do I need to call someone out?
The thermostat is wireless so I put TRVs on all rads but I can take the head off one if I need to.

Shall I contact gas safe to have the system inspected?

Dean
Click to expand...

I would give the installer the opportunity to put it right first to be fair.
 
friendlyaviator said:
Just text him. I've got the commissioning checklist. He wrote down 74 flow 61 return. Does he know this isn't right?
Click to expand...

It is possible he measured those temps. All the more reason for you to ask him back.
Where are you getting the return temp from, Is it on the boiler display?
 
So I text my plumber this:

My boiler is working fine but the flow and return temps concern me. They are only within a few degrees of each other and they are in the 60s. I'm told there needs to be a differential between them. Your views?

He replied:

If the rads are working to your needs that's fine . The boiler temperature is on E so the degrees won't be much more then that.

I'm still concerned about the tiny difference. Currently it's 62/58.

Dean
 
As you heating load is quite small. There will be a lot of time where the return will be coming back without much change. In an ideal world, with oversized rads and a well balanced system you can achive this. A correctly sized boiler will aid in this. But on very small systems it's much more difficult. Especially with a combi, these have very large outputs to the heating. Depending on the boiler manufacturer, your installer can rate it to the system, or some have an automatic rang rating. Thes can be hit and miss.
What make if boiler is it?
 
It's an Ideal logic+ 30 combi. The lockshields were all open when the guy finished.

My heating works fine but I'd like to ensure it's working at its most efficient as so far my gas usage is only marginally lower than before (1984 Concorde WRS heat only)
 
Post 6, AlexGas, has identified part of your problem. If TRVs shut down before room stat. Signal to boiler continues to call for heat, but heat sink (provided by rads) is greatly diminished.
 
joni os said:
Post 6, AlexGas, has identified part of your problem. If TRVs shut down before room stat. Signal to boiler continues to call for heat, but heat sink (provided by rads) is greatly diminished.
Click to expand...

Thanks. I will remove TRV head from radiator in same room as stat. Will this be sufficient.
 
Too many variable to talk you through commissioning the boiler / system I am afraid but L/S's wide open tells us it has not been commissioned correctly.
Whatever has been put on the benchmark cert.
 
friendlyaviator said:
So I text my plumber this:

My boiler is working fine but the flow and return temps concern me. They are only within a few degrees of each other and they are in the 60s. I'm told there needs to be a differential between them. Your views.

Dean
Click to expand...

The difference should be about 20 degrees.
 
How do I bring this difference up? Or is this something I can ask a different plumber to come sort?
 
Your system can be balanced but the heating load is probably tiny once he system is warm and the boilers min is probably alot higher than this. Monitor the temps from cold for a true idea .
 
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