Main Medway Super Water Heater

[jdey]

My problem is:-

1. My water heater cuts out about 1 minute after I turn off a hot water tap.

2. With the hot water turned off, when I re-ignite the water heater, the main burner goes on rather than just the pilot light

3. After a minute, the water heater cuts out because the water temperature has got too high.

4. If I ignite the water heater whilst the hot water tap is running, it will be fine until I turn off the hot water tap when step 3 above occurs once more.

My suspicions are that it's either the gas valve that's stuck open or the diaphragm, but would like a more expert opinion.

 

[twgas]

gas valve is almost certainly sticking open, why it is doing so is the problem, there could be several reasons all of which would need RGI.

 

[Agile]

It seems to be showing very serious signs of neglect and is very dangerous!

You need a competent CORGI engineer who is prepared to repair it. Most will want to replace it!

Tony

 

[namsag]

It is scale on the pin that comes out of the water section and opens gas valve section, because of the scale the pin cannot return properly into water section when the tap is turned off thus keeping burner on.
On older models without overheat stats it causes the pipes to blow off bottom of appliance due to pressure.
Straight forward repair that will take half hour and may require new gland nut or Oring while its apart its just as well to change diaphragm as well for all they cost

 

[jdey]

Thanks for the replies.

I found the instruction/servicing manual here if anybody has a similar problem:- http://www.partsarena.com/baxi/

It does suggest that the push rod between the water and gas valve is prone to scaling and should be de-scaled/re-greased as part of a service.

From inspection, I can see that there is some very slowly dripping water as well, which I guess means there's a very small hole in the heat exchanger. I've been trying to avoid the replacement option as the water heater is tiled in to my bathroom. Not really a water heater issue but:-

1. If I get the replacement model - Medway Multipoint - it's taller than the Medway Super. I'm guessing that most plumbers will say it's not their job to make the gap bigger to fit the larger model but am wondering if this is so?

2. How much is the typical installation cost of a water heater in London? The Medway Multipoint is £270+VAT according to this website - http://www.discountedheating.co.uk/shop/acatalog/Main_Multipoint_Balanced_Fluye.html. I read that it will use the existing flue.

 

[Agile]

1. If I get the replacement model - Medway Multipoint - it's taller than the Medway Super. I'm guessing that most plumbers will say it's not their job to make the gap bigger to fit the larger model but am wondering if this is so?

2. How much is the typical installation cost of a water heater in London? The Medway Multipoint is £270+VAT according to this website - http://www.discountedheating.co.uk/shop/acatalog/Main_Multipoint_Balanced_Fluye.html. I read that it will use the existing flue.

You get what you pay for! Or you get a quote that covers the work to be done!

I fitted an electric Main fanned flue instant water heater last year and we charged £450 but after the job I thought that was rather low a price!

Tony