Installing radiators

Daragh86

I am upside down broke and renovating a house which probably isn't such a good idea but since I'm knee deep in it now I have to get on with it. Anyways my question is about radiators. There is no heating in the house at all at the moment. I am installing a gas combi condensing boiler (not myself) but to cut down on cost I am looking at installing all the radiators and piping myself.

I am splitting the house into two zones so I presume I need to run to seperate circuits of piping from the boiler with the electronic valves on each circuit? My main question is when the water is pumped from the boiler to the radiators, does the water travel through all the radiators then return from the end one directly back to the boiler or does the return from each radiator tee into the return from the last radiator? If the return from each radiator tees into the main return is this with just a normal tee or does there have to be a special value to stop the water from travelling back?

Thanks for any help in advance

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Daragh86 wrote: »

I am upside down broke and renovating a house which probably isn't such a good idea but since I'm knee deep in it now I have to get on with it. Anyways my question is about radiators. There is no heating in the house at all at the moment. I am installing a gas combi condensing boiler (not myself) but to cut down on cost I am looking at installing all the radiators and piping myself.

I am splitting the house into two zones so I presume I need to run to separate circuits of piping from the boiler with the electronic valves on each circuit? My main question is when the water is pumped from the boiler to the radiators, does the water travel through all the radiators then return from the end one directly back to the boiler or does the return from each radiator tee into the return from the last radiator? If the return from each radiator tees into the main return is this with just a normal tee or does there have to be a special value to stop the water from traveling back?

Thanks for any help in advance

I'm not one for giving details on how to pipe heating system over DIY forum, really should be a qualified plumbers job. Down to your situation I'll make an exception.

I'll take it your house is not massive, standard enough etc. Here's just an idea, anything else send a message with further questions.

2 dedicated 3/4" flow and return pipes from boiler to hot press, no tees for rads, nothing just two pipes.

From hot press you then pipe onto rads.

2 dedicated 3/4" flow and returns from hot press to all rads. Try and use 3/4" as much as you can leaving only the last two rads piped in 1/2". If you cant pipe in a way to cover all but last two off 3/4" never have more than two rads piped off 1/2".

All you do is tee off 3/4" flow and return for each rad using 3/4" x 1/2" x 3/4" tees, ideally end of 3/4" rad flow and return will have two 3/4" x 1/2" x 1/2" tee's. If not you might need a few 1/2" equal tees to pick up other rads along the way. If using pex, use inserts @ every fitting along with compression fittings, push fits are not ideal for heating. All exposed pipe work should be copper. All rads should have flow pipe on right, return on left. You'll need a 3/4" x 1/2" spanner, grips, pex cutters (if using pex) and tub of boss white or uniwhite ( pipe jointing compoud). Lenghts of 3/4" pex and rolls of 1/2" pex, you can buy rolls of 3/4" but they are a bugger to work with. Fittings are called 315's for different type tee's, you'll also need some 310's (joiners) for joining up short lengths, converthing pex to copper etc. Might need some blanks too for testing, if you can solder, you can flaten copper rad ends or hotpress ends to solder seal for pressure test.

When you have boiler and rads piped separate you have a few different options over control, if you have two story house you can pipe upstairs rads separate from downstairs. This way, you'll have six 3/4" pipes @ hot press to pick up later when installing cylinder. Once you have all pipes coming to central location ie hotpress, you're well covered.

You'll have to pressure test all boiler and rad pipework before going any further. Hand pumps can be hired in most hire shops.

You have to size up boiler and rads, heat merchants will size everything up for you if you've got house plans, even room measurements along with room description.

Just giving you an idea how it goes, many more things to go over, best send message for more detail.

Tip on rads, after you've sized up when piping add an extra 3" to overall rad length, you might have to drill hole in floor for rad pipes, adding 3" will give you correct center to center measurement to connect rad neatly. For single panel come off finished wall about 40mm, around 70mm for double panel. Nothing looks worse than dodgy looking pipes connecting to rad, if you want to do a good job, measure out, take your time, very easy to have good looking straight pipes picking up rad with above measurements. Finish rad ends with copper, chrome if you really want to be fancy.