DIY first fix advice

[thompo]

Hi guys,

Due to not being able to get a plumber to do first fix on our renovation in a reasonable time frame (tried 5, 1st cant start till mid march/april) Im going to try and do what i can myself.

Im using polyplumb pipe in pipe to run under the floor before insulation and screed is laid.

So i have mounted 2x 3way manifolds in the bathroom these recieve 22mm for hot and cold water. I have run 15mm from manifold to sink and shower and tee'd off at the cold manifold for toilet.

Should the bath get 15 or 22mm?? (havent chosen taps yet so dont know if they are 15 or 22) For the kitchen, i am planning on having only a kitchen sink, no dishwasher or ice maker etc so im thinking 15mm should be fine to the kitchen and the 22 can go to the bath and give extra flow?

Progress so far -

Untitled

• thompo
• 26 Feb 2013
• 2

Untitled

• thompo
• 26 Feb 2013
• 2

Getting tons more clips and some bend supports to get a better radius and hopefully neater installation, Ive left plently of excess on both conduit and pipe incase things need to move a bit. Manifold will be properly secured with additional bracket once everything is in final positon.

Heating circuit has 7port UFH manifold, radiator in conservatory, utility room, towel rail + 2 upstairs rads.

My plan for the heating is to have a central manfold for flow and return beside the tank with runs of 22mm going to the UFH manifold and small remote manifold for the conservatory rad/future expansion (12m run). Utility rad, towel rail and upstairs will be run in 15mm.

Does this sound right?

Couple of general questions, given that the hot water/heating pipes are in the conduit and this is to be covered on 3 sides by (100mm PIR floor) insulation is additional insulation required/recommended? is there best practice with regard to running hot and cold side by side for pipe in pipe systems, minimum seperation distance etc??

Do back boiler pipes have to run in 22/28mm copper and tape/sleeved then insualted? Was thinking of running the pipes now back to the tank, just incase we ever decide to make it work at some point in the future, some of work is already done. The back boiler to coil would have to be pumped with whatever required pipe work/valves for heat dump and vent fitted at the time of comission.


Got to think about the waste pipe etc after this, im told these are best sorted at this stage if i can get them under the floor. But thats for another week lol.

Cheers Neil

 

[Hugh Jaleak]

If hot supply is tank fed, you'll be better in 22mm for a faster filling rate at the bath, bath taps usually 22mm anyway. 15mm is fine for all other hot outlets, and all cold outlets assuming all mains fed.

Unsure as to what type of shower you intend to fit. If a mixer shower is planned you really need independant hot and cold feeds straight from the tanks, otherwise you could get temperature fluctuations at the shower should another draw off be used whilst someone is showering....

You have used the correct inserts in all those fittings ???

 

[thompo]

We are looking at either an Un-vented or thermal store tank so should be getting good flow rates (i hope) on the hot water and all cold will be mains.

Shower type we are looking at is a Vado thermostatic mixer, would you recommend individual feeds or would (should?) the thermostatic valve take care of fluctuations?

Good point on the stiffners
I have removed the seals and rings from the manifolds and fittings at present so i can get the layout right without compromising the connections.
Got everything bagged complete with inserts for making the final connections, if after making the final connections, i have anything left in the bag then ive missed something somewhere lol.

 

[hazetimesfive]

I'm not a fan of waste under floors, if I'm truly honest

 

[zanwan]

I would advice against polyplumb under floors or in any inaccesible place. I prefer to always used soldered copper joints in inaccessible places, far less likely to leak. Polyplumb, if any joints start leaking, you'll have to pull up the flooring/screen to get to it.

I'd strongly recommend copper soldered joints below and just above floor, then connect the polyplumb/pushfit fittings.

 

[Hugh Jaleak]

What size is the cold mains feed into the property? 22mm may be pointless is the mains input is only 15mm, and wont give any advantages as it's limited by the capacity of the mains. 22mm is used for tank fed installations to give a better flow at the bath, but with unvented HW or a combi boiler 15mm is adequate.

Thermostatic shower should deal with fluctuations, but should the cold supply fail then it will shut off the hot supply to prevent scalding.

 

[CBF]

I would advice against polyplumb under floors or in any inaccesible place. I prefer to always used soldered copper joints in inaccessible places, far less likely to leak. Polyplumb, if any joints start leaking, you'll have to pull up the flooring/screen to get to it.

I'd strongly recommend copper soldered joints below and just above floor, then connect the polyplumb/pushfit fittings.

not another one who hasn't got a clue what they are talking about

 

[thompo]

Thanks for the replies,

Water main is currently only 15mm copper but this is being changed to 25mm MDPE whilst the water service are changing their lead supply pipe.

Using the pipe in pipe and manifold system completely removes any joins under the floor, pipes run continuously in a protective conduit from the (above floor) manifold to the fixture.
Means if you do get a leak in a buried pipe, it will fill up the conduit telling you which one it is and in theory you can then pull out the entire length of pipe and feed in the new replacement in minutes.
I have a couple of copper joints to make to existing rads but these will be soldered with any compression/poly joints above the floor.

Not sure if ill get away with the wastes above the floor. Sink and shower would have to run sideways then under the bath to reach the outside.

Is it acceptable to join wastes so i only have 1 pipe going out? Eg bath+shower+sink into one exit pipe? Previous layout had pipes under the floor boards (were going for solid floor) all exiting at individual holes on the exterior wall then running to a drain. means more joints though.

Cheers Neil

 

[Hugh Jaleak]

You can combine the wastes, but the shower would be better on a dedicated waste. (Stops contents of the bath reappearing in the shower!) Fit an anti vac trap on the basin to negate any risk of siphonage when bath is emptied if basin shares same waste.

Use solvent weld pipe and fittings if concealing under the floor, and provide provide rodding eyes at suitable points for future needs.

 

[thompo]

Lol hadnt considered the bath emptying and filling the shower

Duly noted, im heading out now to see what i can figure out for wastes and try to do the heatings circuits, thanks very much the help.