Adding inhibitor to a towel rail

[Harry Singh]

Hi, I know nowt about how what the internals of a radiator look like but is it possible to syphon water from the top to make space for the inhibitor, rather than draining it from the bottom? It just seems easier (if possible) for around 500ml of liquid.

 

[ianmcd]

what boiler do you have and is it a sealed system or open vent

 

[Harry Singh]

Combi - Worcester Greenstar 28i Junior and sealed (I assume).

 

[ianmcd]

probably easiest for you to use this or similar, you can use your filling loop to install it so for a DIYer makes things a lot easier.
https://www.screwfix.com/p/sentinel-x100-rapid-dose-central-heating-scale-inhibitor-300ml/5058v

 

[Harry Singh]

Thanks that looks easy enough. Is there an easy way (for the beginner) of telling which is the cold water supply and which is the system inlet?

 

[Newboy]

System inlet is the 22mm pipe on the right of your photo

 

[Elkato531]

Rapid dose is fine but a bit more expensive. Nothing wrong with your original idea of siphoning water out of the top and then pouring inhibitor straight from the bottle. I do this all the time. Just make sure both valves are closed and any pressure released via the vent before taking the top blanking plug out.

 

[bazdaman]

Plus 1

 

[dilalio]

If you have a spray nozzle from a bottle of something (window cleaner etc) you can put the dip tube of this into the top of the towel warmer and use it to squirt system water out of the rail and into a container... If you use a measuring jug, you'll know when you've emptied enough to make room for the inhibitor

Edit: just a thought... You might have trouble doing this if your towel warmer has a trv valve on it and you don't have decorator caps to close it down fully. Otherwise, manual valves will be fine

 

[Harry Singh]

Everything in our house has valves - so yes it might be an issue if the system was pressurised.

The towel rail's an odd one - the incoming pipe with the valve takes 20 mins longer to heat up than the other rads. The out going pipe heats up in minutes and the railseemes to heat up by connvection to start with. It all seems to sort itself out in the end though. But maybe thta ones for another thread!

 

[dilalio]

So the rail has a TRV for sure?
Take the head off and check the pin isn't stuck.
What's your reason behind adding the inhibitor? Not to try and remedy this problem rad is it? Because that won't work!

 

[Harry Singh]

It's got a valve with settings on (is that a TRV?). I'm trying to sort Expansion Vessel issues and if I can get the water pressure fixed I'll add more inhibitor - it's been re-pressurised a few times so the inhibitor's probably a little diluted now.

 

[dilalio]

If you're having to repressurise a few times then you either have a flat or failed EV; a defective PRV, a leak or combination of the above.

 

[Harry Singh]

If you're having to repressurise a few times then you either have a flat or failed EV; a defective PRV, a leak or combination of the above.

I'm not sure where I am with that at the moment. When I re-pressurised I didn't have the stop cock open so might not have driven all the water out of the EV. It's lost a bit of pressure (gone from 1 to 0.5 bar when idle) over 10 days; but it no longer gets into the high red zone, though it's not had to work too hard in this warm weather.

I'm going to give it one more go, and do it with the drain cock open, then run it hard for a couple of hours to see if it's worked or I need the EV replacing.

Thanks for your help!

 

[dilalio]

Yes. You have to check/add the air whilst water side is depressurised. If you have drain cock open whilst pumping it up, be aware that it will likely push more water out of the drain cock.