Replacing all rads in house - in one go

[dazzlerpalmer]

Gents

I am just about to replace all the rads in the house and refill the system with inhibitor (sentinel).

Is there any way I can do the work over several weekends but still have hot domestic water? I have a single pump with a three way valve. Gas boiler with indirect heating.

I though of draining the system and just using the immersion is this possible or is there a better method?

One guy told me just to switch the three way valve to hot water, drain the system and it will still work. This does not sound right, where does the return pipes go?

I don't want to have to drain and refill on each radiator, but I cannot replace all the rads in one go either.

Any thoughts/ides will be very appreciated.

Thanks

Darren

 

[ChrisR]

where does the return pipes go?

You're right, water on your head. I wouldn't trust a motorised valve not to leak either.

Easiest might be to add a couple of full flow ballvalves on the flow and return.
Or use the immersion heater until you have a couple of rads fitted and put the valves after those.

Running for a week with no or little inhibitor won't do much harm, as long as you do a good clean when you're done fiddlin.

NB the boiler might need a bypass - what is it?

 

[dazzlerpalmer]

Cheers Chris

The bolier is Potterton, located next to the hot water tank and pump & electrics.

Doing the project over say a month or two, I was worried about the sludge build up in the new rads if I kept refilling. I can't afford a power flush so I was aiming to do each rad (taking my time on each) and then do a final fill, drain and refill(with inhib). Its a 1970's house and I don't think the sludge is that bad at the moment.

Where & how would I fit the ball valves (are they 22mm)

Cheers, I was amazed how fast I got a response

 

[ChrisR]

There a a few hundred different Pottertons..! Model/size?

If you're reusing old rads from the 70's then take them all into the garden and invert half full etc (needs 2 people) to get all the muck out that you can. Works very well.


FFBV:

You'll have to work out where the pipes go to decide where to "stop" them.
There will be a Flow pipe and a Return both probably 22mm, with all the rads in parallel, connected between the two (Probably!).

 

[dazzlerpalmer]

Cool,

I think I will identifiy the feed and return, fit these valves. I can then drown the system but leave the hot water on (the Mrs can't go 3 hours without washing something!). It never occurred to me to fit these.

Just one other thing, why may the bolier need a bypass, what exactly is a bypass? - I don't know the model off-hand. It was fitted about 10 years ok so its not an ancient one.

Cheers

 

[kevplumb]

when everythin closes down the bypass provides a path for the boiler to dissapate exess heat
so it dosent overheat

 

[dazzlerpalmer]

I dont want an explosion. I really would be in the dog house (without eyebrows).

I will post the model of the boiler tomorrow. If I could organize the flow and return just within the tank (using these valves) would this be safe?

I could just run the hot water to the house and replace the rads over the next month or two ;o).

The B Gas engineer that came out once told me to cut out the distribution pipes in the loft and clean with a wire brush, then replace and bang in the inhib. I was just planning to replace all the rads and valves - nothing more.

 

[ChrisR]

If there's a bypass it'll probably come off the flow pipe just after the pump, go thro a valve then to the return pipe. Include that pipework if you isolate the boiler, along with the pipes to the feed tank.

How long is BG man's wire brush?? Don't understand.

If it's easy to get at it would be worth inspecting the inside of the pipes where the feed pipe joins - but depends on boiler.

 

[dazzlerpalmer]

The gas man showed me a mess of 22mm pipes in the loft where they spread out to the central heating.
He suggested cutting out all the pipes and re-connecting with compession fittings after cleaning out. He said the sludge would be built up because of all the 90 degree bends here.
From memory I don't think there is a bypass.

 

[kevplumb]

you might not need one

 

[namsag]

You have already said you have a 3 way motorised valve so you won`t need a bypass as this will act as one, at six quid for a 3 metre length of 22mm pipe its not worth the hassle trying to clean it out just change it. Best thing to do is just drain system and use immersion heater over the summer. Also you will have to alter pipework to rads as these now come in metric lengths as opposed to your old ones that came in the number of sections on it and very few match up.

 

[ChrisR]

If there IS a bypass you will have to take note of it when you work on the pipes, whether it needs one or not. They aren't always there just to give a route for water to go.

I wasn't clear if you were putting the same rads back or noe ones. If new than get ones sllightly shorter then you can use small chrome extensions which look reasonable so you don't have to move pipes.

 

[kevplumb]

fink myson still do imperial rads

 

[ChrisR]

Yes they do rads 50mm off everyone else's lengths. PTS do them from stock.

 

[dazzlerpalmer]

The bolier is a Potterton Pr1maF 60F balanced flue.

I had a look and there does not appear to be a bypass there. I think I will have to drain the lot down since the pipes that just feed the heating are not easily accessible.

Since I will go for the complete drain-down. I suspect the immersion heater will f**k up. They are easiliy replaced aren't they. Just spanner off the old one and replace.

Thanks for all the input, really helped. If I had followed the advise from the bloke here we would be paddling now.