💧 Seal leaks, save money, and stay worry-free!
CW4 Central Heating Leak Sealer is a powerful, super concentrated 500ml formula designed to treat up to 18 radiators (150-litre systems). It effectively stops small and hard-to-reach leaks, fixes pressure loss, and is safe for all metals including steel, copper, and aluminium. The product works without needing to shut down your heating system and is non-toxic, biodegradable, and environmentally friendly.
| Manufacturer | CosWarm |
| Part Number | CosWarmCW4 |
| Package Dimensions | 18.2 x 8.6 x 5.8 cm; 453.59 g |
| Manufacturer reference | CosWarmCW4 |
| Size | 500ml |
| Batteries included? | No |
| Batteries Required? | No |
| Item Weight | 453 g |
A**R
Leak sealant- stopped the leak
Used for a very small leak on bathroom radiator union pipe. Worked first time. Pour in, run heating, seal leak. What’s not to love?
K**.
Works well
Kept losing boiler pressure due to small leak under floor. A few days after treatment the pressure is fine.
A**R
OK for small pressure loss,but sadly no help for me.
Leak on garage radiator tap.
A**A
Central Heating fluid.
My husband was very pleased with this item.
A**S
Unfortunately this did not work for me,
Still losing pressure over the space of a week, have a large heating system added two bottles
D**R
Really works
This product really works, had a small leak in boiler and had to top up every 2 days. it sealed the leak within 2 hours.
A**.
Didn't use it
I bought this as the water pressure kept dropping in my boiler and I could not find the reason. This was suggested for treating small leaks in hard to find places. However, the day after I ordered it I found the leak and after speaking to a plumber this was not going to help. One thing I would say is that it is only the bottle is supplied and I couldn't work out how to get this into the heating system. Looking else where you are probably going to need some sort specialised funnel.
R**M
Did the job!
We had a very small leak on a radiator valve and bought this to see if it would stop the leak rather than draining the system and replacing the valve. It worked a treat and no more leak.
Trustpilot
1 day ago
2 months ago
