How to replace filling loop in boiler

[navylark]

Hi, hope someone can offer some advise on here.


Boiler is a Grant oil boiler.

The union that goes into the boiler from the filling loop is leaking from the tap. Unfortunately I had to buy the whole assembly including the braided hose from my local merchants even though I only require the union with the tap connection which goes nearest the boiler end.

My question: If I vent the system pressure by operating the pressure release valve and ensure the boiler has cooled down can I remove the union without draining the system down?

Hopefully I have given enough information, I appreciate that all systems are different.

Cheers Nick

 

[Dannypipe]

Is it an out door Grant boiler.

If so, then I'd suggest you drain the pressure off and go for it as it will save a lot of hassle.

 

[navylark]

Danny

Man that was quick, do you plumbers ever sleep. Yes the boiler is out in the garage/outhouse. I think if there is any remaining water in the system it will be the residual in the pipes in the loft (bungalow) so not a huge pipe run.

I just wanted to check before delving into uncharted jobs.

I have fitted showers and bathrooms as a competent DIYer (25 years as an aircraft engineer) but never in heating system.

Thanks for you feedback

Nick

 

[Dannypipe]

OK - well expect some water. If its in an outhouse it won't be too bad. The fact that its a bungalow means you may not get wet at all, but be prepared. PS - try to drain off the water from a drain valve, rather than activate the PRV as it may not re-seat properly and thus lead you to additional work.

Finally use the time to squirt a can of Fernox F1 into the filling loop. Buy a concentrate tin can from your merchants. Its the easiest way to get it into any system. Not cheap but good routine maintenance, and will more than account for any you have lost draining the pressure off. Ensure you use a can and not a tube that needs a silicon gun to force it in. The cans are so simple. They come with the attachment for the filling loop. You screw it on, pull the trigger and in ten seconds you have enough in there for ten rads'. I then follow with a squirt of water to get the final bit that is still in the hose, into the system.

Good luck, and yes I'm off to sleep now!!

Dan

 

[navylark]

Cheers Danny

1 more question

Do I need any special sealant to seal the threads of the unions or will normal PTFE tape be sufficient.

Cheers Nick

 

[kay-jay]

don't use ptfe on the threads! if you are re-using an olive on a pipe end wrap ptfe around the olive. if you have room to cut off the old bit and still have room to fit new loop on a clean bit of pipe you should not need anything to seal other than the olive

 

[WaterTight]

...but ptfe won't hurt, might help and costs 2 seconds and .001 p for a few turns

 

[Dannypipe]

PTFE was originally designed to seal threaded joints however it does also seal nicely on olives and compression fittings. In this instance you are talking about two olive connections and two 'O' ring connections (normally its an O ring connection between the flexi hose on the filling loop and commpression on the check valves).

In short I wouldn't think you'll need it for the two compression fittings (olives) but it wouldn't hurt. As for the O ring connections (between the flexi hose) you don't want to fit anything as it will only hinder you.

I hope this makes sense.

 

[navylark]

Guys

Thanks for all the advise. Job now complete - haedly any drain down from the pipes in the loft, bit of PTFE tape used for the hell of it and to save any over tightening scenarios. No leaks and boiling working fine.

Wished I had known about this forum when installed my simple underfloor heating system.

Cheers Nick