Drain down cock for SIME Metropolis DGT 25 BF

[Ian Sutherland]

I am hoping someone can help me. I have a SIME Metropolis DGT 25 BF boiler in my static caravan. I have been draining down the van for the winter and was using the service manual to help me drain all the water from the boiler. The manual says to open the 'BOILER DISCHARGE' cock to drain the system, its identified as number 15 in Figure 2. The problem is I can't find this boiler discharge drain cock and I wondered if you could point me in the right direction. All I can see are the standard feeds & returns for HW & CH, the gas feed and what looks like an overflow white plastic pipe which vents to outside.

So far I have opened all the drain valves under the van, one of them is marked for central heating and the water that came out was the radiator water as it smelt of anti-freeze, the other drain valve I opened was plain water but I don't know if it was draining the actual boiler. I have included photos of the inside of the boiler if that would help.

Thanks
Ian Sutherland

 

[tamz]

The boiler will be drained when you opened the valve under the van. There is no pressure on the gauge so you have opened the correct one.

That reminds me i'd better get mine done :wink:

Btw you will need to open any air vents on rads or pipework to fully drain it.

 

[Mike Jackson]

You don't normally drain the water in the heating system in a static van. It should normally contain antifreeze to prevent it freezing. All that you should do is test the concentration and top up if necessary. It's only the hot and cold that you normally drain.

 

[tamz]

Its done now Mike.

 

[Mike Jackson]

This one may be done but if anyone searches for a post on draining down a static they need to know the correct way of doing it. Draining a system is just asking for seized pumps and pinholed rads.

 

[Ian Sutherland]

This one may be done but if anyone searches for a post on draining down a static they need to know the correct way of doing it. Draining a system is just asking for seized pumps and pinholed rads.

Mike: I appreciate what you are saying, but where I am the winter temp gets down to -10 or lower at times and this winter is going to be be the coldest yet. I'd rather go through the pain of draining everything down and refilling again with inhibitor than have a leak or a busted boiler. Thanks.

 

[Ian Sutherland]

The boiler will be drained when you opened the valve under the van. There is no pressure on the gauge so you have opened the correct one.

That reminds me i'd better get mine done :wink:

Btw you will need to open any air vents on rads or pipework to fully drain it.

Hi tamz, thanks for that, so all the boiler parts will be now be empty of water ?. Ive already opened all rad vents and drained rads as well. Thanks.

 

[Mike Jackson]

Mike: I appreciate what you are saying, but where I am the winter temp gets down to -10 or lower at times and this winter is going to be be the coldest yet. I'd rather go through the pain of draining everything down and refilling again with inhibitor than have a leak or a busted boiler. Thanks.

The correct amount of inhibitor will protect down to -18. If you drain down and leave any pockets of water they could easily freeze and cause damage.

 

[Ian Sutherland]

The correct amount of inhibitor will protect down to -18. If you drain down and leave any pockets of water they could easily freeze and cause damage.

I didn't appreciate that, thanks. Then my insurance company insists on draining it down all together, I can't win ...:32:

 

[Mike Jackson]

When I winterise a van I check the level of antifreeze in the heating system and top up if necessary. I then disconnect the cold main, open all outlets and use a small compressor to push all of the water out of the system. Then I'll remove the drain offs on the hot and cols pipes to leave a couple of open ends. I also put some antifreeze (or salt) in the toilet bowls and cisterns.

The most common freeze up is the shower valve. These normally have check valves inside and unless you take them off the wall or blow them through with air water will remain in the valve and freeze up and push it off the connections.

Having said that I normally pass any drain down work onto a local firm who run a guarantee scheme. They drain down and will repair any frost damage free of charge because they are confident of their methods. They charge around £100 for the service.

 

[Ian Sutherland]

When I winterise a van I check the level of antifreeze in the heating system and top up if necessary. I then disconnect the cold main, open all outlets and use a small compressor to push all of the water out of the system. Then I'll remove the drain offs on the hot and cols pipes to leave a couple of open ends. I also put some antifreeze (or salt) in the toilet bowls and cisterns.

The most common freeze up is the shower valve. These normally have check valves inside and unless you take them off the wall or blow them through with air water will remain in the valve and freeze up and push it off the connections.

Having said that I normally pass any drain down work onto a local firm who run a guarantee scheme. They drain down and will repair any frost damage free of charge because they are confident of their methods. They charge around £100 for the service.

Hi Mike: I have done the procedure you detailed except I blew the hot and cold pipes with my mouth over a tap until i heard air gurgling. With the shower valve because of the non return valves, I had to suck the water out of the valve until it was empty. Not very technical but hopefully effective. The site my van is on also provides a drain down service for £100 but to be honest after seeing their plumbing efforts in the past, I'd rather do it myself. I run my own handyman business.

My only problem was finding what the service manual called the boiler discharge cock. Going by the schematic it looked like it should be within the boiler casing somewhere but I couldn't see it, not without moving the control panel out of the way and its still in warranty. I guessed that it should be pretty accessible. Maybe the same 'boiler discharge cock' is actually the drain valves under the van, there are 2, one for hot water and the other central heating. So by disconnecting the main cold feed to the van and opening both drain valves, I've done it all.