Camray 5 oil boiler firing up but no hot water

[benwatkins]

I have a Camray 5 combi boiler in my house which I moved in to in May. It has been working fine for the past four months but last week I turned the hot tap on to fill the kitchen sink and the water that came out was only lukewarm. Ever since I haven't managed to get any hot water out of it at all.

Here's what I have found so far:

1. When I switch the hot water on the burner fires up and the expansion vessel heats up till it is almost too hot to touch.
2. When I turn the tap on I can hear a 'click' sound from the boiler.
3. The red 'lock out' light has come on a couple of times. Pressing the reset button on the top panel clears the light and the burner fires up as in 1 (the red light on the burner does not come on)
4. When I switch the central heating on nothing happens at all other than a click sound. The thermostat is turned all the way up.
5. The copper pipe going in to the inlet side of the pump is hot. The outlet side is cold. All of the other pipes are cold.
6. With the boiler on I can hear a distant purring sound which is difficult to pinpoint but I think may be coming from the pump. It does this regardless of whether the heating or hot water is on.

The boiler was serviced about 3 months ago and the guy gave it a good bill of health. I have used him before and he seems to know what he's doing. Unfortunately he is away on holiday for two weeks and I can't find anyone else around here (I live in a very rural spot). So I have taken to the internet for help.

I do a lot of DIY and car maintenance so I'm happy to do the work myself if it's just a case of changing a pump/valve etc. but I don't know enough about the boiler to diagnose a problem.

Can anyone help?

 

[Burnerman]

I don't think the circulating pump is spinning.....undo the large screw in the middle, insert a fine blade screwdriver and give it a turn.
John

 

[muggles]

I think the click you're hearing is the overheat stat activating, or possibly a relay coming on to activate the pump. I agree with John though - pump is the most likely issue.

 

[oilboffin]

The purring is prob pump humming cos it's stuck

 

[benwatkins]

Sorry for the silence. I had some problems logging in.

For want of anything else to do I tried bleeding the pump following some instructions I found online and it started working again. Haven't had any further problems for a week. So there must have been air in the system which is odd because I haven't done anything to it. The only explanation I can think of is a brief interruption in the water supply. I'm on a private (spring-fed) water supply so it will be prone to fluctuations - although I've been living here for 10 months and never had a problem before.

Anyhow, thanks for the pointers

 

[Terrywookfit]

The pump is in the sealed system. So unlikely.
If system pressure drops air can collect in the pump.

 

[dilalio]

Your pump was jammed. You have unjammed it. It may continue to run for many months to come or it may pack up very soon... it's a common device to have to replace when needed!