urgent help plz: ravenheat HE85 T boiler overheat red light

[psarinuk]

Hi

I've a Ravenheat HE85T boiler, very similar to CSI85T model.

Recently, the boiler stopped working and red (overheat) light came on. I checked the thermisters, they were OK. The pump was not working, although there was 240V supply @ pump, so I've changed the pump.

Even after that, the symptoms are still the same. I put CH or DHW ON, the fan starts in low speed, the pump starts(I opened the big bleed screw and could see the pump running inside now) but the red light comes after 5-10 seconds..

There is no flame (looking through the window), so how does the overheat light come on? The fan does not seem to go full speed, so could it be fan or air pressure switch? Could it be some air lock but I thought the air inside boiler (drained a few times) goes automatically through air vents..

My worst fear is ignition control board (main PCB) and I hope that never comes true..

I hope I get some replies and many thanks in advance for that..

 

[Agile]

I think you will find that an ignition failure light.

If the fan is controlled by a fan driver PCB then that might well have failed.

They often fail but not usually exactly as you have described.

Your fault is bordering on a gas/combustion fault which may need a gas registered engineer.

Tony

 

[psarinuk]

Could you plz explain ignition failure light? What part are we talking here?

The fan relay PCB was exchanged exactly 1 year ago (credit card size PCB). Should I try the old one again and see if it makes any difference?

I do not believe that its a gas combustion fault, reason being before ignition, the fan comes on full speed which it is not at the moment. The fan is not oscillating either..

 

[Agile]

I really think that you are delving into parts of your boiler associated with the gas/combustion without the training or skills to be able to do that safely.

I must therefore advise you to get a registered gas engineer to investigate.

Tony

 

[psarinuk]

Could you advise of any good honest registered gas engineer in/ around Basildon, Essex.
Anyone on this forum?

 

[psarinuk]

Worked out it was easier to phone Ravenheat than look out for a competent REGISTERED gas engineer.

Turns out that fan PCB was faulty after checking fan voltage (130V). Voltage from faulty fan PCB was about 300V and I've put in the old fan PCB that I had replaced exactly 1 year ago.

Apart from frequent cycling in CH mode when boiler is cold, rest is fine.
I would still need to change this semi-working PCB soon. Any idea on warranty on these parts?
The one I replaced in Dec 08 is a genuine ravenheat part.

 

[Agile]

The original fan PCB is an admitted design problem.

Its not clear to me exactly what you have done about the original failure.

The problem is that the PCB failed to provide the slow speed and so the boiler went to lockout when it modulated down towards minimum. That was usually the situation when the heating was up to temoerature after 10-20 minutes.

John will not be pleased with me for saying this but try hard to get them to send you a new one. You can argue it had a design fault and was "not suitable for the purpose".

Tony

 

[psarinuk]

Which is the original failure out of these:

1. Due to a faulty fan PCB the boiler was constantly refiring in CH mode 1 year ago. This was replaced with a new fan PCB. The boiler was working fine since then.

2. Recently, when the boiler stopped and the RED light came on, the NEWLY REPLACED fan PCB (1 year ago) was not giving enough voltage for the fan to run high speed. When I replaced it with the old one, the boiler has started working fine for DHW but the constant refiring when cold is still there for CH. So I need yet another fan PCB.

I phoned Ravenheat and they said I need to speak to the supplier (with the name similar to highly flammable gas) or I can send the part for diagnosis for £40 fee (which would be refunded if part is faulty).

Supplier says they are unsure of Ravenheat warranty, but I can send the part back, but still have to buy a new one. They will refund the cost of old part if its deemed faulty from Ravenheat.

Phew! Hope it confuses, sorry clears the matter more..