Draining performa primary circuit to change CH/HW diverter

[tukky142]

Hi,

I tried to drain my combi's primary circuit yesterday by isolating the feed and return, turning off main water supply and then opening drain tap. Once the drain stopped I tried to remove the CH pressure diff cover plate to replace the diaphram but was met with loads of water that would not stop. Am I missing something? - Is there an other way to get the water out of the system or do i have to just catch the water until it all runs out

 

[kevplumb]

methinks you didn't open the hot taps and drain the h/w

 

[tukky142]

i thought that when metwith thewater so went down and opened taps but thisdidnt stop the water. I have a problem with a sticking diverter valve could this be the problem?

 

[croydoncorgi]

You have to turn off the COLD SUPPLY to the boiler!!!

 

[tukky142]

I had turned the cold supply to the boiler off. - I have tried again today - turned off the feed and return valves and the cold water supply - opened all the taps in the house but nothing comes out???? - any ideas

 

[corgiman]

well it wont come out as its a direct feed

did you try to change the wotsit?

you will still get a fair amount of water so have towels and a bucket at the ready.

if everything is turned off and your are getting nowt from either the hot and cold taps AND the drain off has stopped running there will only be what is left in the boiler.

 

[tukky142]

yes i did try to change the ch pressure diffdiaphram but gave up when the water wouldnt stop coming out. I now now that i have to use towels and wait until the water stops

 

[croydoncorgi]

You should only have to empty the hot pipes.
When you've turned off the cold supply, open a hot tap upstairs (above the boiler) and another below it. That should drain out all the water.... but still stand by with a towel.

And in principle, there's no need to drain the heating circuit. All the pressure and water in the diaphragm valve comes from the cold supply, not the rads.

 

[ChrisR]

Not reading again CC!
- what he did was

try to change the ch pressure diffdiaphram

WHich would need the boiler pressure letting off then either:

Drain water from the CH system (drain cock at rad or similar) to below the level of the boiler,

or
Use the boiler isolating valves, then the boiler drain, to empty the boiler.

You take a chance using iso valves, they can leak afterwards.

For the tap water diaphragm the previous advice is ok.


However,, tukky, it apoears you may be confusing the two diaphragms. The big one, domestic tap water one, is there to notice that a tap has been turned on and make the diverter valve work.
The small one, the CH one, is for the boiler to tell that the pump is pumping water. Nothing to do with the diverter (almost).
"Primary" does not specify which is intended - it's a term used only on conventional boiler systems, where it refers to part of the heating pipe circuit.
"Hot pipes" isn't terribly useful as a definition, either!

 

[tukky142]

Thanks ChrisR - Agile has told me to leave the CH pressure diaphram alone as it does have anyhting to do with my problem. My diverter is sticking and when on HW alot of the heat is going down the CH feed pipe instead of going down the HW pipe. I have removed the actuator motor from the top of the diverter and this should position the diverter to HW but still most of the heat is going down the Feed pipe when there shouldnt be any going down there.

Looks like a whole new diverter valve

I have another post going at the moment that Agile is responding to - please refer to this one now - thanks

 

[Agile]

Good example of why you should stick to just one thread where all the info can be read!

How many times do I have to repeat that the "CH diaphragm" as you insist on calling it, is required to operate its switch on both CH AND DHW ! Thats why I prefer to call it the system flow switch.

You dont have to replace the whole diverter if you are competent to open it up and get a pile of springs and rods and rubber seals!

Moose head?

Tony

 

[tukky142]

I am not touching the system flow switch!

Did you see my reply to you on my other thread? I did remove the diverter motor but still had heat going down the feed pipe when HW tap was open. I also checked the HW microswitch and this too was ok.

I am now going to get a new diverter valve - is there a best sequence to changing it? - What about replacing seals on all touched joints? Should I order replacements?

Have you used MJTcontrols.com?

I have ordered an new valve and all new seals for all disturbed joints - Would the valve come with a new temp sensor?

 

[Vic Spanner]

Would the valve come with a new temp sensor?

No it dose not...Also if yours is the instant version Be extra careful when draining the primary circuit down as there is water stored in the pre heat/ expansion vessel and there is a certain knack of draining that out. Good luck.

 

[tukky142]

What is the knack? - I was going to drain the boiler using the drain tap and also drain the rads down a bit so there isnt any water nearthe boiler.
What else can I do apart from having loads of towels at the ready?

Another question - there is a connection into the back of the diverter valve with a nut joining the by-pass pipe to the diverter - what is the best tool for unding this joint as there is minimal space under the combustion chamber.

 

[tukky142]

Has anyone changed a diverter on a performa 28i? Can anyone recommend a sequence of removal - plus any special tools used?