Do I put an expansion tank on my system?

[saxmanuk]

Hello
I have recently had my Dansmoor 32/50 oil burner (discontinued in 2001 model) serviced and it is running well at 93% efficiency. Great!
I was chewing the preverbal with the heating engineer and I mentioned that is took me ages to refill the system after I fitted two new rads...because the header tank and the subsequent meters and meters of pipe to the burner does not have the head to fill the system up. I used the trick in the FAQ re temp fixing a pipe to the expansion pipe and forcing water down that way etc etc. and it worked fine.
To the nub...the engineer suggested I fit an expansion tank (18l) next to my burner which would make the system sealed and also have the benefits of pressurising my whole system of 19 rads and will also help in my having to bleed the upstairs rads every month or so
What do you think?
Is this sound advise please?

 

[saxmanuk]

Any views experts?

 

[Hugh Jaleak]

Sealed systems are modern alternative to open vented, and have their advantages. However, converting an older system may bring problems. It will be working at higher pressure, so any weak spots will manifest themselves as leaks.

There is a reason for your frequent need to bleed rads. It may be a result of corrosion within the system, or could be a small air leak on the suction side of the pump. Not enough to let water out, but enough to let air in when under negative pressure. This may reveal itself if the system was pressurised!

To convert to sealed system you will need a filling point, pressure gauge, and a pressure relief valve with external discharge at a safe point as well as an expansion vessel.

 

[saxmanuk]

Many Thanks for your reply
I will consider your view

Thanks again

 

[Hugh Jaleak]

If corrosion is an issue in your system, (black water from rads, sediment in F+E tank are 2 pointers to corrosion taking place), then it is also possible there may be partial blockages in the pipework, hence taking so long to refill. Again, (if corrosion is an issue), there may be pumping over occurring, this will pull air into the system, and accelerate rate of corrosion.

If you didnt add fresh inhibitor after draining then this wont help, assuming there was inhibitor present beforehand! Converting to a sealed system will only slow down, not prevent corrosion unless the system is adequately dosed with inhibitor.

 

[saxmanuk]

Hugh

Many thanks again for your reply
As for the past few years, before I moved into the house, I dont know if it had x100 in it or not.
I flushed the system then added x400 for 4 weeks and now have x100 in again. When I flushed after the x400, it removed loads of black sludge and dirty water.
I will most likely fit the expansion tank and hope that I find no weak spots.....then again better to know if I have weak spots and to fix em early

Thanks