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Remove + add 3 new radiators in a bay. + speedfit or not.

Postby el-d » Tue Mar 10, 2009 1:40 pm

Hi All,

I'm new to plumbing but consider myself an able DIY'er but wanted to check a few things first.

I am planning on removing a radiator in my living room and replacing it with 3 radiators that will fit under the bay window (yes angled/ curved would be better but much harder to get and more expensive).

I assume that they are connected as follows:

Incoming pipe - valve - rad1 - rad 2 - rad3 - thermostatic valve- outgoing pipe.

I assume that one thermostatic is all that is required. Would I need locking valves in between?

I've read about balancing rads, what is the best method fo r 3 in a row or do they really just count as a single rad?

So as a course of action, are my steps as follows.

1: shut boiler/CH off.
2: drain through tap on radiator ( can only see 1 or would there likely be a tap under the floorboards?)

3: Remove the old radiator
4: Fit /position brackets for new rads ( I guess this could be done 1st)
5: Fit new pipework
6: Cut old pipe and attach to new pipe for in and out.
7: Refill and check for leaks.

A few questions :

I assume Speedfit would be the best (although more expensive) route for me as a novice.
Does it require the cutting tool? They say not to use a hacksaw due to burring etc but can this not be sanded smooth? or can a stanley knife cut through ok?

How flexible is the plastic piping as far as connecting between rads ?based on the short distance that will be between each rad.

Any tips/hints/advice welcome.

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Simply Build It

Postby plumbbob » Tue Mar 10, 2009 8:33 pm

Connecting up the rads as you suggest may result in the third rad in the row getting barely warm at all. Because each rad has to totally fill with hot water before the outlet side begins to warm, will mean also a significant time delay before the third begins to get warm. Far better to plumb traditionally and fit a feed and return to each rad.

Only use plastic pipe where it is not seen as visibly it is ugly and looks dodgy DIY. Take a length of copper from the rad tail straight down through the floor and then into plastic. (You do have hollow floors?)

You can cut plastic with a Stanley knife, but believe me it is serious watch your fingers!!! Apart from avoiding bloodshed, ensure the pipe is cut exactly at 90 degrees otherwise it will not plug in properly and may leak.

It is important not to mark the pipe in any way by scratching or sanding. If you do, the rubber seal will not make a watertight joint. Even the swarf from a hacksaw cut is sufficient to destroy the seal.

Oh, and there could be a drain tap under the floor, but I wouldn't hold my breath. Depends how generous the installer was.
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Postby Steve the gas » Wed Mar 11, 2009 5:45 am

Also TRVs better on flow but most a bi-directional now.
Balance with lockshields.
Steve the gas
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Postby rosebery » Wed Mar 11, 2009 7:00 am

As Bob says pipe each rad correctly or the heating solution will be no good. If you are going to use plastic it should not show above the floor.

The whole point about using the correct cutting tool is that the O ring doesn't get damaged when you push the pipe into the fitting. 9 times out of 10 pushfit connections fail becuas ethey aren't properly made up in the first place - pipe cut correctly, use the proper insert, ensure pipe fully home in fitting, don't mix and match different manufacturers stuff.

Given the relatively short distances involved frankly you should do it all in copper - you will find it much easier and certainly cheaper.
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