Single Pipe

[DISCO DAVE]

Hi

As many just discovered our new house has a single pipe system despite a few modern radiators, new bathroom and new Combi.

It works just but is very noisy as pipes badly cut across joists so ticking follows the heat around the system and the ground floor vertical column radiators are not great and probably wrong for the system with the tails so close together.

Up against it time and cash wise for having all repiped ( 3 ground floor, 4 first floor, 1 top floor).

Is it possible to phase the rollout of the two pipe, ie T off flow and returns for the ground floor rads only as two pipe leaving capped connections for rolling it out to the upper rads later.

Main reason for this is we are supposed to lay hardwood floor and fit kitchen to ground floor this week so won't be easy to do this later. Upper floor is carpet so a pain but can roll it back and move furniture to get boards up at later date.


Could we just T the new flow and returns direct off the exisiting or would we need some sort of valve control to ensure the two loops continued to function? Is this even possible with a Combi?

Cheers All, hopefully have a quote for doing the work tomorrow, but they will need a week apparently so will miss our moving date and possibly worse our kids school applications but its also a sort of now or never.

 

[ericmark]

We have a single pipe system on the trains we run, loads of ambiance as the steam comes out of last carriage, but I am sure that is not what you mean by single pipe system?

The modern gas boiler is often controlled by the return water temperature, there are two ways to control the extraction rate at the radiator, one is how much water flows through it, the other is the speed of the fan, with the latter there is no restriction to flow rate, so if they were piped in parallel the boiler could shut down prematurely, so series works better, but with the former use of a by-pass valve allows faster boiler response when piped in series.

There is no best or worse system, it depends on the layout of the home, type of heater, type of heat exchanger (radiator) and access as to what the heating engineer who designed the system thought was the best method at the time.

Times do change, we have a problem with Santa special trains, if the steam engine fails, it takes ages to fire up a replacement, so only option is diesel, but then there is no steam to heat the carriages, we saw last year how another heritage railway were using diesel powered heaters, but these needed a 12 volt battery to run them, so battery needed charging over night, and the diesel tanks needed topping up each night, we have considered a change, but the steam engines in spite of being over 100 years old, don't break down that often, so not really worth it.

Be it a train or a house, we have to consider is it worth changing.

 

[denso13]

Is it possible to phase the rollout of the two pipe, ie T off flow and returns for the ground floor rads only as two pipe leaving capped connections for rolling it out to the upper rads later.

Yes, although it may affect the one pipe rads you leave in place.

 

[DISCO DAVE]

All, not sure trains are quite the same, but I do appreciate the not broke don't fix, they changed the Bristol London line to electric then failed to complete so made hybrid now its slower and heavier than the old diesels.

However at the moment we have no carpets or flooring down so best time to rip into it.

Its a simple design, a 1 inch loop feeds two downstairs rads, then the upstairs 5 then back down to the last one in the living room and back to boiler. That rad doesn't get hot but as the return is hot at the boiler I reckon its plumbed badly or possibly one directional or sludged up.

Plan would be to blank off the tails to the one pipe for the ground floor rads so the loop runs for upstairs only

We would then plumb new two pipe to the three ground floor rads and T into the flow and return near the boiler..

Do we need some sort of balancing valve on the flow to ensure adequate flow to each loop as they assume they will have different resistances, not sure we have any pump control with the Combi.

We would propose running all the new pipe work and installing new rads but have a plumber install any valve connections for the flow and returns and possibly pressure test it all first.

Makes sense in my head but have had one plumber suggest phased is fine and another say it categorically won't work and rip it all out now.

To go full two pipe now doesn't look that much work as only some locally lifted flooring required, awaiting a quote but not hopeful they can do it in time.

Any thoughts appreciated, my problem is we are supposed to fit carpets Friday to 1st floor and stairs and move in next Wednesday! EEEEEKKKKK so access will be lost.


Schematics attached, one pipe in pink on the section, two pipe proposals only on the plan.

 

[Madrab]

TBH if you are quite handy with pipework then converting the 1 pipe to 2 pipe isn't a huge amount of complexity, especially if underfloor access is easy. The hardest part is routing of the pipework then it's just the cost of the materials

Take a 22mm F&R pipe along from boiler up to the 1st floor and then into the hall, then it's just running branches out in 15mm and a 15mm feed up to the 2nd floor.

I'd suggest you do it before the carpets go down otherwise it will just be a large amount of grief later on.

 

[DISCO DAVE]

We might go for it, but time is against us, not that handy with plastic but have done a fair bit of copper and one of us has done a good bit of plastic for bathrooms same principles.

Got a plumber on site tomorrow cutting of some old gas connections for us, will ask him, maybe he could supervise a bit.

For the top bedroom 4 radiator, we can't easily run a new flow and return to it at the moment without boxing out into a bedroom, we might be able to connect the old one pipe connections as tails from the 1st floor level flow and returns. Tails would be a bit long though at 5-6m but the heat should rise for the flow or do we absolutely need to run the flow and return loop nearer to the rad.