Fitting TRVs to an old sytem Help please !

[Joely]

Hello fellow plumbers,

I am really close to finishing my first year at college and my Brother in law has just bought an old house. On the survey it picked up it had no TRVs. I really fancy helping them out and trying to do the job as i feel it will be straight forward but just want to check some advice from online first.

Ok here goes, From looking at the system i think its a fully pupmed indirect open vented system.

there is a room stat in the hall way which i assume turns the boiler off when it get to the correct temp

The central heating pipe work is small bore and its a 2 pipe system seperate flow and return

So shall i just drain the whole system, fit all new small bore trvs, put inhibitor into the sytem via f&e and fill one rad at a time ??

Now as its an old sytem i dont know if its full of crap or whats gonna happen.

Oh and one of the bedroom has no heat in its radiator at all, i have felt the flow and retuern pipes and they are both cold. Shall i follow the flow under the floor untill it get hot ? do you think it could be blocked etc ?

Any help gratefully accepted

Cheers Joely

 

[glenno1]

Your pretty much right.The bedroom rad you mention may have air lock but it may cure itself when you refill the system

 

[Joely]

nice one thanks, The million dollar question how do you work out the order of your rads ?

 

[SimonJohns]

Your pretty much right.The bedroom rad you mention may have air lock but it may cure itself when you refill the system

I disagree with that. Make an attempt to get it working now. (turn off all other rads etc.)
If it then doesn't work I would dose system with a strong cleaner and leave. For a few days and retest afterwards

This will rule out alot more potential issues and also save you time and money on draining and refilling.

 

[SimonJohns]

What do you need the order of that rads for?

Balancing?

If the system is what you say it is. Just work away from the pump

 

[jtsplumbing]

Id'e run a good system cleaner through first Fernox F5, then replace all valves Look at Bulldog valve sets (Plumb center) made by peggler, TRV's can be fitted either end. Fill up with Fernox F1. Rember not to put TRV in same room as room stat ! What do you mean by order of rads ?

 

[Joely]

Thanks everyone, i ment when refilling the sytem so it doesnt fill with air. You are gonning to have to bare with me as i have never done a job this big before.

Ok so how do we clean they sytem before replacing valves ?

 

[TBServices]

Partially drain down, pour the cleaner in the tank, fill up again. Leave it for as long as you like (as long as you don't go over the limit set by manufacturer)


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[jtsplumbing]

Drain part of system so that all cleaner is taken into system then run for a week with heating /water on hotter system getts better cleaner works, Get your self a rubber mallet to bang along bottom of rads, helps shake up sludge in bottom of rads, drain system when hot, let it refill a couple of times (Cold) with pump running to rinse out system, replace valves and refill with inhibitor, 1ltr will do up to 10 rads if you have a lot of big rads put in 2ltrs.

 

[Joely]

Ah excellent i will suggest we start with this first, so once we have left that for a week or so how should i go about investigating the cold rad in the bedroom.

Also what would be the benefit of cleaning a sytem if your gonna drain it when you replace all the valves anyway. Will this help pull all the crap out when we drain down ?

 

[jtsplumbing]

Yes spot on just as well give it a clean, as you dont know state of system water, remember to clean out F&E tank, cold rad could be somthing as simple as Turned off or full of air, may even be valve stuck up with dirt from system.