Advice on fitting TRV's to my radiators

[schott19]

Hi All,

First time poster so hello to everybody in here and really hope you can help.

I have an old back boiler system (with one of those hideous ceramic gas fires on the front ) which just has a digital timer unit so im assuming no thermostat other than the one attached to the back boiler (under said hideuous fire).

What i want to do is to put thermostatic radiotaor valves on but i wanted to ask a few questions with regards to this:

1. Is it even a good idea / worth it to put these valves on with having such an old system (i will upgrade to a combi at some point but if it aint broke..)

2. I have seven radiators - do i need 7 valves as in my research i have heard something about leaving one without a trv - but this may not apply to my system - im just not sure to be honest. If i do leave one without - which one?

3. I understand that i need to drain my system to replace all the valves and lock sheilds (most current ones are corroded or leaking a bit) but when i fill it up i read it is good to add an additive to the water - is this true and if so which is best? i saw one called Fernox Alphi-11 but unsure if thats any good.

Really hope a professional out there can help me. Im not a plumber but though id try and have a crack at it myself - just a little stuck / concerned about a few bits and bobs

ANy help greatly appreciated,

Thanks!

OH, if it make a difference - i have bought Danfoss C2 15mm (just the one so far to check they will fit)

 

[bengasman]

before you start changing valves, make sure the system is clean. I have yet to find the first back boiler that is not full of you know what.

 

[schott19]

Hiya,

Thank you for your reply. How would i go about cleaning the system? is this something i can do myself?

Thanks

 

[bengasman]

read FAQ, you will find most of your questions answered

 

[D_Hailsham]

1. Is it even a good idea / worth it to put these valves on with having such an old system (i will upgrade to a combi at some point but if it aint broke..)

Yes.

My son's house has an old back boiler. If the living room was OK, the rest of the house was often too hot, particularly the bedrooms. So we put TRVs on all rads but one; problem solved. If you do change your rads, you can always swap the TRVs to the new ones.

I have seven radiators - do i need 7 valves as in my research i have heard something about leaving one without a trv

That's correct, you need 6 rads with TRV and one rad without a TRV, which is controlled by a wall thermostat. Which rad depends a bit on the layout of your house. Some say the rad in the living room and others, the rad in the hall.

I understand that i need to drain my system to replace all the valves and lock sheilds (most current ones are corroded or leaking a bit)

There are ways of changing valves without draining but, guessing what condition your water will be in, it's probably better to drain down.

You should try to have a clean system before fitting TRVs as they can get blocked by crud. So flush the system through with cold water, until it runs clear, before changing the valves. For a better clean, flush through with water, refill and add Sentinel X400 cleaner, leave for a couple of weeks, flush again. Alternatively, remove each rad and flush through with a hose in the garden. Then change your valves.

i read it is good to add an additive to the water - is this true and if so which is best?

Sentinel X100 and, if you live in a hard water area, also add Sentinel X200.