2 quick plumbing questions

JohnBoy

In our house (oh yes, we moved in 3 weeks ago, its a diy fest)

The oil boiler and circulating pump are on a timer. when the timer is on, the pump is circulating, and the boiler cuts in and out according to its thermostat.

should the pump always be circulating? or should it switch along with the boiler? or should it be independatly thermostatically controlled?

In an unrelated task i want to replace 2 sections of pipework in a room we're rennovating upstairs. they are badly done in a qualpex/copper mix and don't follow the contour of the wall. we will be dry lining the wall so I want to re-do the pipework flush with the wall so that it can be hidden behind the skirting board at the bottom of the dry lining.

to do this i'm gonna need to use presolderd fittings to keep snug to the wall. I have a butane blowlamp, standard cheap yoke runs off those little cans of camping gaz where the torch actually pierces the can, anyway I'm rambling, do I need to get a mapp torch or is the basic butane one gonna be hot enough?

Doolittle51

JohnBoy wrote:

should the pump always be circulating? or should it switch along with the boiler? or should it be independatly thermostatically controlled?

Yes, the pump should always be circulating when the time switch is on.
I don't know much about your other question, sorry.

beldin

1/ The pump should be connected to a constant live and not via the timer. The pump should be turned off and on by the thermostat. Otherwise if the boiler was on and then then the timer turned everything off you would have very hot water in the boiler which can cause banging.

2/ A standard blowlamp should do, just clean both sections of pipe and then put some flux on the ends of the pipe. Insert the pipes into the fittings and then clean off any excess flux. Then heat up all around the joint until the solder flows all around the joint. Removing excess flux stops the solder coming out of the fitting.

JohnBoy

haven't noticed any banging yet, and the timeswitch is indoors with the boiler house being fed by it, so i don't really have an option on a constant feed.

i'll leave well enough alone so i guess

been told by someone else just now that my torch should be fine, which is good, because a mapp torch would cost 50+ euro, but is bad, cos a mapp torch would be a fun toy to have.

Pataman

beldin wrote:

1/ The pump should be connected to a constant live and not via the timer.

I dont think you are right. The pump and boiler are connected to the timer. The pump runs constantly, when turned on by the timer, and the boiler trips in and out according to the temperature of the thermostat in the room and on the return pipe. The pump must be on to allow constant monitoring of the return pipe temperature.

sundula

pump controlled by a pipe stat on the return - i think

Doolittle51

Pataman wrote:

I dont think you are right. The pump and boiler are connected to the timer. The pump runs constantly, when turned on by the timer, and the boiler trips in and out according to the temperature of the thermostat in the room and on the return pipe. The pump must be on to allow constant monitoring of the return pipe temperature.

Agreed

JohnBoy

the boiler thermostat is only mounted to the top of the boiler's housing, there seems to be a sensor wire loop that goes in through the top of the boiler's housing, but on the opposite side to where the pipes enter.

the boiler's a firebird 90.

the system is working at the moment, i've had to do a few mods/tweaks to it already, and there's some pipes to come out and be replaced but it is working.

JamesM

JohnBoy wrote:

the boiler thermostat is only mounted to the top of the boiler's housing, there seems to be a sensor wire loop that goes in through the top of the boiler's housing, but on the opposite side to where the pipes enter.

the boiler's a firebird 90.

the system is working at the moment, i've had to do a few mods/tweaks to it already, and there's some pipes to come out and be replaced but it is working.

There are lots of dodgy statements above.

In most systems, When the timer switches on, the boiler comes on and is controlled by its own thermostat. The boiler should always be kept up to temperature and should not be controlled by a room stat.
The pump also comes on - but can run through a room stat and switch on and off depending on the room temperature. Alternatively, The pump can also run constantly when the timer is on, and the flow to the hot water and rads can be controlled by motorised valves controlled by thermostats. If there is a gravity feed from the boiler to the hot water cylinder, the pump is not needed for heating water only. But it is needed to heat the rads. There are naturally other scenarios. These are the most common.
Jim.

JohnBoy

this setup pre-dates motorised valves by a bit I reckon

thanks for all the suggestions anyway people