How to fill inhibitor where no valve on top of radiators and magnaflow filter cannot be opened. Sealed unvented central heating system

[Samsg30]

Hi,

I have old style radiators where there only a small bleeding nut on top of radiators and the bathroom doesn't have towel rails either.
The magnaflow filter is sealed with jointing compound to avoid leak from the sealing rubber so I can't open it without replacing the whole unit

Attached is the picture of the radiator. The whole system was flushed 3 times in last one month to fix various issues so I think it's worth putting inhibitor but don't know the best way to put that in.

Any pointers appreciated

 

[Samsg30]

Forgot to say it's a sealed unvented central heating system with no f&e tank. It has red expansion vessel.

 

[oldbuffer]

Have a look at Sentinel's "Rapid Dose". Pressurised container injects into radiator via bleed screw. In theory you don't have to reduce pressure provided its less than about 2 bar. In practice I find them fiddly to use, and its better to reduce pressure to zero then refill.

 

[Mottie]

Close both rad valves on one rad, drain the rad, remove the bleed screw and use something like this to get the inhibitor in. Refill rad, repressurise system and run it up to get the inhibitor circulated. Job done. Other sizes are available but you’d only need 10 shots with this syringe to get a litre of inhibitor into the system.

 

[Harry Bloomfield]

Close both rad valves on one rad, drain the rad,

No need to completely drain it, just drain it enough to leave space for the inhibitor. You can get syringes much cheaper than that.

100-500ML Reusable Big Large Plastic Hydroponics Nutrient Measuring Syringe UK | eBay

Find many great new & used options and get the best deals for 100-500ML Reusable Big Large Plastic Hydroponics Nutrient Measuring Syringe UK at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

 

[Mottie]

You can get syringes much cheaper than that.

Where? It’s less than a fiver Harry. It'd probably cost you more than that by the time you’ve paid for fuel, bus fares or parking!

 

[Harry Bloomfield]

Where? It’s less than a fiver Harry. It'd probably cost you more than that by the time you’ve paid for fuel, bus fares or parking!

See my link to ebay..

 

[Mottie]

See my link to ebay..

My one comes with a tube so that’s why it’s a whole £1.23 cheaper.

 

[Harry Bloomfield]

My one comes with a tube so that’s why it’s a whole £1.23 cheaper.

How do you know the tube will even fit the bleed hole?

 

[fixitflav]

The magnaflow filter is sealed with jointing compound to avoid leak from the sealing rubber so I can't open it without replacing the whole unit

How are you going to check and empty the magnaflow in that case? Break the seal and reseal it afterwards. If it won't reseal replace the thing. It's also useful for sampling the water for a corrosion test.

 

[Samsg30]

Thank you all for the useful replies.
I'll use the Rapid dose after draining the radiator a bit to allow enough inhibitor in. It's slightly more expensive but given only to be done once in a while, it's less fiddly than other useful methods like syringe and tube etc.

 

[kidgreen61]

Magnaclean seals only cost pennies, get a new one.

 

[DP]

Close both rad valves on one rad, drain the rad, remove the bleed screw and use something like this to get the inhibitor in. Refill rad, repressurise system and run it up to get the inhibitor circulated. Job done. Other sizes are available but you’d only need 10 shots with this syringe to get a litre of inhibitor into the system.

View attachment 310398

It can be done but is tad messy as there will be a blow back unless there is means to keep the pressure at zero typically like on a rad with two tappings. Often a towel rail is found lurking in the bathroom which is ideal for dosing the system.

Concentrated chemical for use in caulking gun applied via filling loop is an alternative

Went to a job one time where the plumber and householder had fallen out. The plumber took the bleed pins

 

[Samsg30]

Magnaclean seals only cost pennies, get a new one.

When plumber opened it last time to clean, rubber was found broken and it started dripping so he used PTFE and jointing compound to seal it since he couldn't find seal locally and can't wait for 2-3 days for it to arrive online. He told me that it cannot be opened now because we'd be replacing whole heating system in next 18 months during renovation, so he thought it's OK to leave that as it is.
Not sure if that was an intelligent decision as such but I won't open it unnecessarily if it was cleaned recently and I can get the inhibitor via other mechanism.

 

[Samsg30]

It can be done but is tad messy as there will be a blow back unless there is means to keep the pressure at zero typically like on a rad with two tappings. Often a towel rail is found lurking in the bathroom which is ideal for dosing the system.

Concentrated chemical for use in caulking gun applied via filling loop is an alternative

Went to a job one time where the plumber and householder had fallen out. The plumber took the bleed pins

Any reason why would there be pressure in the rad if both valves are closed and some water is taken out of rad by temporarily loosening the valve nut to drain a litre of water?