Baxi Solo 2 40 PF problem..

[Messer]

Hi,
i am new to this forum and was looking for any advice really..

I have a Baxi Solo 2 40 PF boiler and recently its been acting up a bit. When its on, quite frequently you can hear a continuous electrical buzzing noise which may last for about 20 seconds or so and then stop. It sounds like a relay clicking, you can see a bit of interference through the TV when it does it, a little like holding a light switch in half way for example.

Its been doing this for the last month or 2, but this morning I went to turn on the heating, click, hum, stop. Click, hum, stop. Click, hum, stop. you get the idea.. that cycle repeats! The pilot light isnt coming on....

My friend is a corgi plumber, and we had a look at the PCB today as the noise appears to be coming from there (it definately is) but could anything else cause this or should I just replace the PCB?

Thanks

 

[Boilerman2]

Check the Resistance of the Pilot Solenoid coil (left hand coil on the gas control Valve) the resistance should be 1.5K/ohms, if it is not near this figure the PCB may be struggling to perform the start sequence, remove both wirers from the solenoid before testing with the multimeter set to 2k scale

 

[Messer]

Ok Cheers I will have a look. Excuse my ignorance, but where is the gas control valve?

 

[kevindgas]

in the bottom section has a grey cover usually.
the solenoid is changable on these and is a regular part to fail, usually no need to change the whole gas valve.

 

[Messer]

Ok, so if the covers are off as i look at the boiler would it be in the bottom right corner there are two things - one has the gas pipes coming in and the other is like a cylindrical item with 2 spade connectors connected to it.. Is that what I should be testing?

Cheers
Tony

 

[Messer]

I've disconnected the wires and checked the resistance, I'm getting 1.52 with my multimeter set at 20k and 1542 when its set to 2000 ohm.

Does that mean anything?

 

[rojaca]

1.5 K/ohms or 1500 ohms. Both same thing. What you're looking for.
I'd suspect a faulty relay on the board. Did you check for any dry joints when you had a look at board?
Sorry Boilerman- am stealing your thunder here.

 

[Messer]

Just wasnt sure with it being 1.52 when set to 20k, Kevin suggested 1.52 when the meter is set to 2k....

There was a dry joint on the board which we have resoldered but to no avail.

There is a small patch on the board which looks a little discoloured slightly, but its surrounded by resistors so it could be those getting warm maybe..

We did suspect the PCB originally but wanted to be 100% certain before I buy a non returnable product

 

[rojaca]

20k is the upper limit that it will read up to. It will also give the reading in the set range eg ohms kilo-ohms or mega-ohms.
One of the other chaps may be able to help you a little more on the testing the board etc. It's nice to have a van full of parts but it tends to make you a little lazy when it comes to testing.