New boiler worry

Canucklehead

callmechar wrote: »

so this is bad or good? RGI is approved by WB

Bad. See Post 11.

callmechar

gas4you wrote: »

8.2% is way too low for this boiler.

As Keystone rightly says it should be 9.8/9.2 %, but unusually I have to respectfully disagree with his comments about the boiler running at 8.2% minimum. (Sorry Keystone)

With such a low reading on minimum, you will, or may eventually get ignition lockouts.

You also may get the boiler shutting off when it modulates down, rather than just ticking over on minimum.

Has your installer said he cannot set the minimum to 9.2%, or does he just not know how?

There are lots of installers who just fit a boiler on the wall and leave it.

What is the working pressure at the gas meter and the inlet pressure at the boiler gas valve?

Your installer should have checked both of these with such a problem as this.

I also hope he gas rated the appliance at full power, whilst in your case I would have also gas rated it at minimum power as well.

On the face of it, setting the gas valve on one of these is a POP.

Thanks. Now I am worried. Emailed him again

callmechar

I have 2 logs printed out. They state:

LET BY TEST
PRS_1 m bar 10.82
PRS_2 mbar 10.94
LET BY MINS 1.00

Tightness test
PRS_1 mbar 19.98
PRS_2 mbar 20.07
PRS mbar -0.09
STABIL'N MINS 1:00
TIGHTN'S MINS 2:00


Combustion
02 6.5%
co2 8.2%
Co ppm 9
Flue 0c
INLET 47.1 degrees C
NETT 0c

XAIR 45.1%
co/co2 0.0001
PRS mbar -0.02

gas4you

Hmm. You should have also had a combustion test done at full power.

The combustion figures you state are way out for this boiler at minimum power and considering most modern boiler will be running at near minimum power the majority of the time, this needs sorting.

Your previous statement that the gas pipe is 22mm, means absolutely nothing without details of pipe length and bends/elbows and whether any other gas appliances are running off the same gas pipe work.

Most of my installs these days have to be 28mm, with occasional ones in 35mm.

You need to ask your installer what he is going to do about these combustion readings and if he does nothing, ask gas safe for an inspection.

callmechar

gas4you wrote: »

Hmm. You should have also had a combustion test done at full power.

The combustion figures you state are way out for this boiler at minimum power and considering most modern boiler will be running at near minimum power the majority of the time, this needs sorting.

Your previous statement that the gas pipe is 22mm, means absolutely nothing without details of pipe length and bends/elbows and whether any other gas appliances are running off the same gas pipe work.

Most of my installs these days have to be 28mm, with occasional ones in 35mm.

You need to ask your installer what he is going to do about these combustion readings and if he does nothing, ask gas safe for an inspection.

Thanks Gas4you

This is very worrying. RGI offered to come back Saturday and re test the boiler - but sounds like he needs to do more than that? What is it he needs to do? Can he fix this? I am quite concerned.

The 22mm is from the meter under stairs - comes out of their (we are end terrace) and goes outside along end of terrace wall and back in kitchen, so not many bends. We only have a gas fire too. We are getting a gas hob soon too.

What would Gas Safe do? Would they come round and inspect his work? Would they fix it?

gas4you

It is nothing to be worried about in terms of safety.

It just needs to be set up or recommissioned. It could even be a faulty gas valve, which would be under warranty, and absolutely nothing he has done wrong.

Remember, we can only reply as to what you post.

The boiler needs to be set up for 9.8% co2 when forced to maximum setting, then forced to minimum setting and set to 9.2% co2.

When this is done it needs to be set to forced maximum setting and gas rated.

This will confirm it is running as designed for.

The Working Pressure at the gas meter should be checked with the boiler on maximum, then the inlet pressure at the appliance checked on maximum. In theory there should be no more than a 1mbar drop between them, but in the real world you may get slightly more.

The new gas pipe should have been sized to allow for the boiler, fire and the proposed new gas hob to all be on full and the pressure drop remain within the above allowance.

Gas Safe will attend, if requested, to do a safety test and report only. They will not undertake any improvements if needed.

See what your installer says on Saturday. It could all be a storm in a tea cup and get sorted in 30 minutes.

Canucklehead

OP: bottom line is...your RGI should not have left your boiler as is i.e. not commissioned according to WB specs. Ensure he has completed the Benchmark Log..page 67 in the installation manual , the warranty is registered with Worcester and the installation notified.

Let us know how you get on this Saturday.

Canucklehead

callmechar

Thanks

He has completed the commissioning checklist (pg 67) and in "all installations" "if required by the manufacturer record the following...Co2" - he has put 8.2 and written something, looks like low read or something?!

gas4you

Well, we wait in anticipation for tomorrow!

callmechar

UPDATE

RGI been back. His new readings are below. Taken 5 mins apart:

Low flame:
02 4.9%
C02 read is now 9.1% C02 (not 9.2% in manufacturers spec)
C0 ppm 9
FLUE 0 degrees
INLET 21.7 degrees C
NETT 0 degrees C

XAIR 30.6%
C0/Co2 0.0000
PRS mbar -0.24


High flame
02 3.6%
C02 read is now 9.8%
C0 ppm 65
FLUE 0 degrees
INLET 22.3 degrees C
NETT 0 degrees C

XAIR 20.8%
C0/Co2 0.0006
PRS mbar -0.27

Are these better please?