Combi boiler not supplying hot water
 

Girlfriend called me up earlier, turns on the hot tap, boiler fires up but
no hot water is supplied, just runs cold. So it seems to me the pressure
sensor is working? What else could it be? Not sure of the Manufacturer,
begins with M i believe, gonna pop over there later and take a look. Any
suggestions appreciated.

thanks,

L

Combi boiler not supplying hot water
 

"John Smith" wrote in message
...
Girlfriend called me up earlier, turns on the hot tap, boiler fires up but
no hot water is supplied, just runs cold. So it seems to me the pressure
sensor is working? What else could it be? Not sure of the Manufacturer,
begins with M i believe, gonna pop over there later and take a look. Any
suggestions appreciated.

thanks,

L


How long does the boiler fire up for ? Is it only staying for a couple of
seconds or is it staying lit the whole time water is being demanded ?

Combi boiler not supplying hot water
 

On Wed, 26 May 2004 08:54:05 +0100, John Smith wrote:

Girlfriend called me up earlier, turns on the hot tap, boiler fires up but
no hot water is supplied, just runs cold. So it seems to me the pressure
sensor is working? What else could it be? Not sure of the Manufacturer,
begins with M i believe, gonna pop over there later and take a look. Any
suggestions appreciated.



There's firing up and there's firing up. Many people will say the boiler
is firing up when all they mean is the fan starts.
So check if you have a flame, if you have then the problem must be a stuck
diverter valve (and the radsa will get hot eventually).
If there is no flame then dived and conquer is the way.
Air pressure switch?
Ignition?
Gas Valve?
PCB?

(Don't jump to the last two untill you are 110% sure it's not the first
two).

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html

Combi boiler not supplying hot water
 

Thanks for your reply,

I've found out it's a Myson Midas wall mount combi

The boiler is 'working' as the rads are hot, the boiler seems to whirr up
into action as soon as the hot water switch is turned on, and it continues
to whirr until switched off again, but not change or click when the hot
water tap is turned on, and no hot water.
Off to investigate now anyway. Going to try and locate this divertor valve
and pressure switch first then...wherever they are.




"John Smith" wrote in message
...
Girlfriend called me up earlier, turns on the hot tap, boiler fires up but
no hot water is supplied, just runs cold. So it seems to me the pressure
sensor is working? What else could it be? Not sure of the Manufacturer,
begins with M i believe, gonna pop over there later and take a look. Any
suggestions appreciated.

thanks,

L

Combi boiler not supplying hot water
 

John Smith wrote:
Thanks for your reply,

I've found out it's a Myson Midas wall mount combi

The boiler is 'working' as the rads are hot, the boiler seems to
whirr up into action as soon as the hot water switch is turned on,
and it continues to whirr until switched off again, but not change or
click when the hot water tap is turned on, and no hot water.
Off to investigate now anyway. Going to try and locate this divertor
valve and pressure switch first then...wherever they are.

I'd say that your diaphragm in the diverter valve has gone, check this by
manually lifting with a screwdriver the micro switch which it controls (with
a hot water tap on) - new diaphragms cost around 10-20 quid.

Jon

Combi boiler not supplying hot water
 

In message , John Smith
writes
Thanks for your reply,

I've found out it's a Myson Midas wall mount combi

The boiler is 'working' as the rads are hot, the boiler seems to whirr up
into action as soon as the hot water switch is turned on, and it continues
to whirr until switched off again, but not change or click when the hot
water tap is turned on, and no hot water.
Off to investigate now anyway. Going to try and locate this divertor valve
and pressure switch first then...wherever they are.

** The Myson Midas has two separate pumped systems, one for hot water,
one for central heating. I don't think there is a diverter valve (it's
been a while since I tested any midas boards)

** The Midas also doesn't have an air pressure switch, it has an air
flow sensor which is basically two NTCs, one in the air flow, one not.

I would check that the pump impeller hasn't broken off the shaft first.
Then check out the hot water flow sensor.

Do you have a manual for the boiler, you'll need one. There are a series
of LEDs on the main pcb which indicates what the boiler is trying to do.

There are two versions of this boiler, one has a 404C147 main pcb
(usually blue), the other has a 404C656. They work slightly differently
to each other

Be warned, his is a complicated boiler, you might have let yourself in
for a little more than you first thought.

--
geoff

Combi boiler not supplying hot water
 

In message , Jonathan Pearson
writes
John Smith wrote:
Thanks for your reply,

I've found out it's a Myson Midas wall mount combi

The boiler is 'working' as the rads are hot, the boiler seems to
whirr up into action as soon as the hot water switch is turned on,
and it continues to whirr until switched off again, but not change or
click when the hot water tap is turned on, and no hot water.
Off to investigate now anyway. Going to try and locate this divertor
valve and pressure switch first then...wherever they are.

I'd say that your diaphragm in the diverter valve has gone,

No, it doesn't have one

check this by
manually lifting with a screwdriver the micro switch which it controls (with
a hot water tap on) - new diaphragms cost around 10-20 quid.

Jon



--
geoff