CH ok, no HW [Combi boiler]

[need-help]

I installed a Heat Line C24 combination boiler, 7 month ago, replacing a baxi 100.
Came home yesterday, no hot water. The CH is working, but not as efficent as it has been. The indicator lights on the front of it, are not flashing.
I realise it is still under guarantee, but with me fitting it, the waranty may be void. so I guess it is up to me to repair. If possible.
As with anyone else, any help will be much appretiated.

 

[need-help]

I forgot to add. When heating running, and HW called for, it over rides the CH and turns the burner off all together.

 

[possum_jenkins]

Most probably dhw thermistor ( sometimes refered to as NTC's / PTC's / Temperature sensor ) fault.

Only cost £20 or so and easy to replace, you'll find the position on your manual, not familiar with this boiler so unsure if it is wet pocket, but most are so likely you'll need to drain down.

You can test it by isolating power to the boiler, and testing resistance across the thermistor with a multimeter , if you get less than 1 ohm or infinity then you have faulty one.

Remember to disconnect the wires from the thermistor first as you may pick up resistance from the PCB.

 

[need-help]

Thank you for your sugestion. I checked resistance between the poles on the switch, and all ok. Although it has rulled out the temp sensor, I am still no nearer. There is a 3way valve with a big electrical block on it, and I do not have any resistance through the 3 connectors on it, could that be the problem ?
,
Any other help will be appretiated.

 

[need-help]

It aimt the motor on the end of the 3 way valve. I took it off and it was working. the spigot on the end of the 3 way valve, is free enough ie it pushed in under pressure, and sprang out with the internal spring !
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With no hot water, any sugestions, please foward to, Dirty mick, lancashire. [thats me]

 

[mehran]

Well, for a start you should of not fitted the boiler your self. a good corgi reg'ed engineer should be able to fix it no problem. I am a service agent for heat-line but giving you advice about fixing your boiler would clearly be un-wise.

My best advice is to find a corgi reg'ed engineer to come out and make sure that your install is safe then phone heat-line and say that you have fitted the boiler your self and would like a heat-line agent to come out and fix it and is willing to pay...

They may be willing to come out...maybe

 

[need-help]

A self righteous attitude like that, is whet I dont need, but thanks anyway. ,
Yes sir, I do know, I should not have fitted it myself. but quite a few of us on this site, can ill afford to pay someone to do the job. That is why the site is called what it is! [DIYnot] I also realise, it is sometimes more expensive in the long run, to do the job ourselves. Also it is more dangerous, but my other option, when the last boiler was past repair, was to freeze.
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Again sir, thank you for your coments.

 

[Slugbabydotcom]

The CH is working, but not as efficent as it has been.

Points me in the direction of the CH thermistor.
If its wet pocket [in the system water] the chances are the system wasn't flushed properly and its coated in crud.

I wont rule out the possibility of another fault possibly in the region of the flow switch

 

[need-help]

Thank you for your sugestion, slugbabydotcom. If you mean the DHW thermistor, it aint wet pocket. It is affixed to the pipe with a couple of clips, and on checking for resiatance.it is ok.
Also when its wires are disconected, the boiler will not fire up at all, even for CH.

 

[Slugbabydotcom]

CH thermistor.

If you mean the DHW thermistor,

No I mean CH thermistor.

 

[need-help]

Hi. I just removed the heating sensor leads. Switched on the boiler, and it would not fire up, on CH. Replaced them and it fired up imediately. Which I guess, tells me the heating sensor is ok!

 

[need-help]

Is there any possibility, it is the diverter valve?

 

[Slugbabydotcom]

Hi. I just removed the heating sensor leads. Switched on the boiler, and it would not fire up, on CH. Replaced them and it fired up imediately. Which I guess, tells me the heating sensor is ok!

Bad guess! That tells you naff all

Have you tested the resistance of the thermistor with any values given in the MI's. Have you taken it out to see if its coated with crud because the system hasnt been flushed properly? Try replacing the thermistor with a 10 k resistor and see what happens.

Why do you want to throw money away on a diverter valve when the most obvious culprit is much cheaper to start with? You might as well save up the £156 or whatever for a BG one off repair. If you qualify you may be able to get a one off grant for a repair of up to £300 from WARMFRONT

I do sympathise with those who can't afford to get proper jobs done which is why I am giving advice when others have stopped, but I can see this turning into a comedy of errors.

 

[need-help]

Firstly let me say the boiler is OK now,and thank you for your assistance.
.
I took your advice, and called in a Heating engineer. He diagnosed the flow censor, having spoken to Heatline. He ordered one which arived the following day. Fitted it, and it made no difference. He then told me it must be the circuit board, at a price of £135. Having just spent £35 on a flow censor. I asked him to sort the pipes out, and meke it look like a profesional fitted it! It took him an hour, to put the condensing pipe through the wall, also the drain off pipe through the wall.He charged me £120 for his effort.
.
I callede out Heatline. there fitter came the following day. It took him 10 minutes, to diagnose, and fit a new heat sensor. I checked the thermistor, and there is resistance, but that accounts for nothing. With all the lights on at the front display, it tells the boiler the water is hot enough, so dont fire up...
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Thanks also to Heatline.

 

[possum_jenkins]

yes sorry, perhaps my advice was bad advice. Thermistors can also lose callibration which will give you a resistance, but not a correct one. As slug said above, the manufacturer have tables which detail the corect resistance present for a given temperature. Unfortunate you had to shell out but glad you didnt give into the "pcb's knackered mate" drivel!