Potterton 80e keeps locking out after HW use

[Noisy]

My Potterton Puma 80e locks out fairly frequently, (but not all the time), after using hot water. I have noticed it more when the CH is off.
About 30seconds after stopping using the HW, a horendous sound builds up, like a train rushing through the pipes, the pressure rises to about 3bar, then there is a sound like water being shot out a pipe, the pressure drops to about 1bar, then back to about 1.5bar and the boiler locks out.

Any suggestions for things to check (easily)? I don\\\'t want to pay for new pumps, PCBs etc if it is something simple/cheap/easy to fix.

Thanks.

 

[breezer]

i am not a plumber or heating engineer, i dont have the same boiler you do, but have a look at this

(top of yopur boiler LHS, and see is that where the noise comes from (dont touch it, and when ours did that (potty puma 100e) thats where noise was coming from

 

[Noisy]

Breezer, what is it? Did you replace yours? Did it solve your problem?

Noisy

 

[breezer]

I think its called an Auto air vent it was changed, but it didnt solve the current problem, we have a contract with b gas, so they do everything, but I wondered, is it your one that makes all the noise, ours still does on occasion

 

[defmeister]

My 100e does the same thing. DHW flow switch is sticking, a few hard raps with a screwdriver handle helps for a few days!!! About £40+vat for a new one.

 

[ChrisR]

It IS the DHW flow switch. Pokinga scrwdriver into the aperture where the spring is will often clear it till the next time. Thay can be taken apart for cleaning but a new one is better.
DoO a search on "Absolutely" for an explanation. Used to find it anyway!

 

[defmeister]

Told ya

 

[Noisy]

An Engineer came round this morning, went through the fault finding procedure, and came to the same conclusion. The DHW flow switch (diaphragm) has now been replaced. It has been OK so far, but as it was an intermitant problem, I will reserve judgement for a few days. I guess I am just a pessimist!

Thanks for your help everyone. I will try to remember to provide a progress report in a week or so.

Noisy

P.S. Where is "Absolutely"?

 

[ChrisR]

Absolutely lost.
Email me for description of how it works and what to do.
anotherletterbox at aol.com use the @ symbol

 

[DP]

Noisy- What has been replaced- hot water flow switch or the diaphragm?

 

[Noisy]

How water flow switch was replaced. Cost £180 inc a general service and parts.

Has been fine so far, except hot water temperature seems to vary fluctuate now whilst showering.

 

[TheIce_Man]

£180 !!!! jesus can i come service your boiler - there is a sucker born every minute! probably only needed the switch cleaning and adjusting using the nut.
Mama mia