C/H Problem - New pump solves it after 6 months!

[Richard Faulkner]

Hi,

some may recall my posting about a C/H problem where my Jaguar boiler cut out intermittently, and never when an engineer was looking at it.

On 5 occasions over the 6 months, 3 different heating engineers looked at it, and none could/would diagnose the cause.

It was definitely an overheating problem, with F1 error code meaning the thermostat next to the heat exchanger needed resetting, or F3 error code simply meaning an overheat of something, and where it would fire up without attention, once the temp had fallen.

I discussed faulty pump with each of them, and none were sure saying that they didnt want to spend my money when it could be something else.

Over time, and listening to them, and to the boiler, (including a screwdriver to the pump and my ear), I recognised that the sequence was:

thermostat demands heat, boiler fires up, pump runs for a period from a few seconds, to a few hours, pump stops, temp rises, thermostat cuts the gas.

I was therefore reasonably certain that either the pump was faulty, or something was stopping power getting to the pump.

Eventually, I insisted that one of the engineers fitted a new pump to test my theory, and it seems to have worked a treat.

What a job I had to get one of them to do it! I had to insist that it be done, and that I wouldn't be upset if it didnt work.

I guess that I am probably luck to have such honest engineers, who dont want to spend my money unnecessarily, but it has been a frustrating 6 months with sporadic, or no heat.

Why am I writing this?? Well, I suppose it is to say that there seems to be no real way of diagnosing the cause of a problem with certainty, and it may be necessary to spend money on a number of possible cures in order of reasonableness, in order to exclude particular things.

[Rick Dipper]

Sir

Thank you for your story, I just sent it to my boss. I hope he understangs the analagy, to todays reason for chewing my b***s.

Rick

[Niall]

You are up against the problem that most of the GBP are totally unable to grasp this point, and also expect everything to have an infinite life. Tradesmen rapidly learn this.

I have a similar problem trying to get my vehicle maintained. The industry is geared to customers who won't accept that something needs replaced until it physically falls off, not even then if the vehicle can function in some manner without it. I OTOH want anything which is not certain to last to the next service, replaced.

[Alan]

In message , Niall wrote

If it ain't broke don't fix it.

For safety reasons it may be prudent to replacing brake parts etc.at the recommended service intervals but replacing components just for the sake of it may not make your car more reliable.

Most people expect the engine in a modern car to last until it goes to the scrap yard - but it may fail before the next service! Is it better to change it, just in case?

[Ed Sirett]

I suppose the order in which things are tried to resolve an intermittent problem is partly 'reasonableness' = likelihood of being the culprit. partly the cost of the item and partly known track record.

For over heating this would normally be either a flow related problem or a faulty sensor.

So if the temperatures of the boiler seem reasonable then pumps, bypasses (or lack), All TRVs+ warmth are reasonable.

Given that over heat sensors are cheap they are probably changed as the first or second item on the list.

A pump is simple to change and is still much less costly that a call out so that would be the next up. Although an intermittent pump failure is not common IME. (Open circuit, Earth fault, Total erosion, or duff capacitor would be the usual suspect).

The PCB would be towards the end of the list (unless a Suprima).

For instance if someone reported delayed or no CH after DHW on a Puma then you might aswell go and get a diverter valve actuator on your way there.

[Niall]

Replacing things that are broken but can still be used, OTOH, will, and usually makes the driving experience rather more pleasant.

It may, but if it's not smoking or displaying other symptoms it probably won't. OTOH, if the brake pads are not down to the metal but clearly don't have another 6000 miles in them, I suppose you'ld rather the garage left them until you've had the use out of the very last bit of friction material then go through the whole fandango of booking it in, getting back from the garage, not having the vehicle, getting back to the garage, running the risk that there wasn't as much left as you thought and wrecking a disc...

[Alan]

In message , Niall wrote

But you was writing about replacing parts that were not broken.

If it's obvious that the pads are not going to last you could ask the garage to change them. I know of no garage that would turn down money if offered :)

On the other hand, do you trust all garages to tell you the truth when they are short of work? During an MOT one garage told me that the brake disks although okay for the MOT were getting thin and they needed replacement soon. They offered to do the work in the following weeks. Ten and a half years later, and ten MOTs, the car was scrapped with the same (original) disks!

I've always considered pad and disk replacement an easy diy job.

[Niall]

Not as I read what I wrote.

The point here is I pay them to service the vehicle at the manufacturer's intervals on the basis that for instance I do not have to monitor the condition of the brake pads in the interim.

If they are going to do that they have to balance the profit they will make doing it against the future profits they will lose if I find out they did it. It being fairly obvious that I know my way round a vehicle.

I did car mechanics myself when I had to. I no longer have to, and would rather do what I do to earn the money to pay someone to work on my van. I don't have a garage big enough to take the vehicle let alone have room to work on it, and being in the west of Scotland it invariably starts to rain as soon as I start to work outside. The last time I had a set of discs replaced the mechanic certainly didn't think it was easy. I saw the remains of the old discs, and I believe him.

[Dave Plowman]

Go for a BMW, then. They're very good at recommending replacements that aren't needed. ;-)

[Dave Plowman]

Yes - on some cars they weld themselves on.

[Niall]

They don't make vans.

[Dave Plowman]

Some would disagree.