Worcester Bosch Highflow 400 HW Too Hot

Webbo13 · 28 Jul 2009

Can an experienced Gas Engineer help please?

Newly qualified Gas Installer and my first fault is on a Worcester Highflow 400. The customer reports that very very hot water is coming out of her taps, not scolding, but too hot to put your hands under.

First thought, HW Temp Thermostat, this is a discrete ON/OFF thermostat. Tested with multimeter and is functioning. However, I am questioning if the thermostat is still properly calibrated as all other components within the boiler appear to be operating fine. I have checked to ensure that there are no kinks in the capillary tubing from the phial to the stat body - all ok. No real reason to suspoect PCB at this point in time.

Has any one else had this probelm and if so what was the solution? I am reluctant to charge a customer / provide an estimate before being 100% sure of the exact problm. Many thanks in advance for your help!

LMannix · 28 Jul 2009

Without wanting to insult your inteligence have you checked that the hot water dial is moving the pot on the pcb? Have you turned the temp stat down and ran the water through?

Dont forget the 400 has a small tank of stored water, so if after a few minutes of pulling the hot water through you still have this problem you would then have to go through the usual check list of stat, pcb, the water flow through the heat exchanger isnt slowed due to scale etc

Agile · 28 Jul 2009

Webbo13 said:
I am reluctant to charge a customer / provide an estimate before being 100% sure of the exact problm.

Many thanks in advance for your help!

One thing that you will have to learn soon is that you should NOT go and diagnose a fault free of charge!

If you do that then they will just change the part themselves. You must always charge for diagnosing the fault.

We fix the fault free apart from spare parts but we do charge to diagnose the fault.

In this case the complaint is arbitrary in that a matter of personal opinion as to what is too hot. They can be difficult to resolve because most of those compaints result from wrong settings of the controls by the user.

Tony

Webbo13 · 29 Jul 2009

Thanks for the responses. The boiler is a highflow 400 BF and so the HW dial does not directly act on a pot on the PCB. The HW dial / thermostat is electrically wired to the main PCB via to pink wires to terminal X2, pins 1 and 2. Thansk for the suggestion though.

I have now received another call, saying the overheat thermostat has not tripped out and they are getting no hot water at all! Guess who will be taking the blame for that then... Instructed them to reset, but warned it is likely to trip straight back out again after 3 mins use. Any more suggestions?

The MI's are not helpful as the Fault Finding guide does not cover the scenario of very HW. I understand that if the HW plate to plate is partially clogged, slowing down the flow, then you are going to get hotter water coming out despite the thermostat setting.

Thanks to the other reader about not diagnosing without being paid..point well made!

D_Hailsham · 29 Jul 2009

Agile said:
One thing that you will have to learn soon is that you should NOT go and diagnose a fault free of charge!

But the OP said "Newly qualified Gas Installer and my first fault." So it is obviously a fault which he has never encountered before.

Would you be willing to pay someone to learn how to diagnose a fault if he did not have the required experience? It might take the OP an hour or two to do what you can do in ten minutes. There are numerous accounts on this forum of the "the chap fiddled around for ages, he did not seem to know what he was doing" variety.

Webbo13 · 29 Jul 2009

Thanks D_Hailsham, I did think that this forum was here to help others not to shake their confidence when embarking on a new career in the middle of a recession. Cheers

Deleted member 105431 · 29 Jul 2009

Webbo13 said:
Thanks D_Hailsham, I did think that this forum was here to help others not to shake their confidence when embarking on a new career in the middle of a recession. Cheers

a career for which you are clearly unskilled at; I wouldn't want you working in my house.

g20 · 29 Jul 2009

ouch!

D_Hailsham · 29 Jul 2009

dangermouse46 said:
a career for which you are clearly unskilled at

Inexperienced, yes; and the OP acknowledges this. But that does not mean that he is unskilled.

It's the old panel beater's bill story:

Hitting car door panel with hammer - £5.00 (skill)
Knowing where to hit - £25 (experience)

Deleted member 105431 · 29 Jul 2009

D_Hailsham said:
dangermouse46 said:

a career for which you are clearly unskilled at

Click to expand...

Inexperienced, yes; and the OP acknowledges this. But that does not mean that he is unskilled.

It's the old panel beater's bill story:

Hitting car door panel with hammer - £5.00 (skill)
Knowing where to hit - £25 (experience)

new entrants like him are ten a penny and none of em have a clue. the public just see the cheap (free in this case) labour and lap it up.

anyone who works for free is desperate and a fool.

Boilerman2 · 29 Jul 2009

I hope that rabeye34 is reading this post, as this is exactly why everybody is giving him the good advice they have (New to Gas Work)

ollski · 29 Jul 2009

If you're new to diagnosis my best advise is steer well clear of highflows. The dhw heat exchanger will almost certainly be blocked and it stinks to do. You cannot access the hx to check flow temps directly.

Rosy · 29 Jul 2009

No disrespect meant to anyone but if I had to pay for a diagnosis and it was wrong I would not be happy to pay again.

We had 6 visits in one week to our Highflow 400. The first 5 were from the same engineer who could not find the problem. The 6th from a different engineer who put right what the first had screwed up on his first visit.

Thankfully this was courtesy of a BG contract, if I had had to pay for each of these visits I would not be a happy bunny.

Deleted member 105431 · 29 Jul 2009

Rosy said:
No disrespect meant to anyone but if I had to pay for a diagnosis and it was wrong I would not be happy to pay again.

We had 6 visits in one week to our Highflow 400. The first 5 were from the same engineer who could not find the problem. The 6th from a different engineer who put right what the first had screwed up on his first visit.

Thankfully this was courtesy of a BG contract, if I had had to pay for each of these visits I would not be a happy bunny.

my point exactly. were all 6 visits BG?

Rosy · 29 Jul 2009

Yep. On the 6th I requested a different engineer because the first one clearly had no idea what he was doing. He kept saying it was a complicated boiler and fitted lots of different bits, none of which were the problem, only the new thermostat he had fitted on the first visit. Also on his first visit he had tested the gas pressure, said it was way too high (preset) and turned it down to half and messed with the inside of the flue, both of which the engineer who made the 6th visit corrected.

I've got all the worksheets and exactly what they did.

Like I said if I had had to pay for the callouts and parts I would not be happy.

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Worcester Bosch Highflow 400 HW Too Hot

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