Draining a Morco gas water heater

[blackrose]

How do you drain a Morco gas water heater? My old valiant was very easy to drain but I can't figure out which is the drain screw on this one.

 

 

[Ian F B]

47 minutes ago, blackrose said:

How do you drain a Morco gas water heater? My old valiant was very easy to drain but I can't figure out which is the drain screw on this one.

 

 

Small screw at top of white 

pipe,if I remember correctly!

[blackrose]

1 hour ago, Ian F B said:

Small screw at top of white 

pipe,if I remember correctly!

 

Thanks, I thought it might be that, but i expected some sort of drain spout so you can collect the water in a cup of small container and it doesn't go everywhere. I guess I'll just put a towel down there.

[blackrose]

I don't think it's that screw. Water shoots out of it but it doesn't drain any water in the heater. Unless that water is being held by a vacuum.

[system 4-50]

https://morcoproducts.co.uk/resources/D61B_D61E__G11E_Manual_English_1000524605.pdf

[blackrose]

Ok thanks. Looks like that is the drain screw. How come nothing is draining? 

[Alan de Enfield]

12 minutes ago, blackrose said:

Ok thanks. Looks like that is the drain screw. How come nothing is draining? 

 

I think you need to disconnect the cold supply otherwise it is generating a vaccum.

[blackrose]

You'd have thought there would be a bleed screw somewhere to release the vacuum?

 

My old valiant was much simpler to drain than this Morco

[springy]

With the L port valve set to the morco position, open the hot taps - this should allow the water to drain - most will probably drain from the tap with just a dribble coming from the drain point.

 

springy

[blackrose]

Ok I'll try that. Thanks.

[TheBiscuits]

21 minutes ago, springy said:

With the L port valve set to the morco position, open the hot taps - this should allow the water to drain - most will probably drain from the tap with just a dribble coming from the drain point.

 

springy

 

 

The only bit this technique won't drain is the only bit that breaks if it freezes ...

 

 

 

3 hours ago, blackrose said:

 

The pressure disk is in the housing that looks like an an oyster or a flying saucer, dead centre underneath.  One bleed screw - use it with a bowl underneath.

 

I do agree that it will get backpressure from the domestic hot water system, so fit an isolator to both the flow and return.

 

 

As an aside, next time you use a holesaw in timber, do a shallow cut with the holesaw on the visible side before cutting the main hole ...

[springy]

9 hours ago, TheBiscuits said:

The only bit this technique won't drain is the only bit that breaks if it freezes ...

 

I should have included "Remove Drain Screw" in the sequence, though it would have to be removed for a dribble to come out of it. The amount of dribble may depend on the height difference between the taps and the drain point.

 

springy  

[blackrose]

9 hours ago, TheBiscuits said:

 

 

The only bit this technique won't drain is the only bit that breaks if it freezes ...

 

 

 

The pressure disk is in the housing that looks like an an oyster or a flying saucer, dead centre underneath.  One bleed screw - use it with a bowl underneath.

 

I do agree that it will get backpressure from the domestic hot water system, so fit an isolator to both the flow and return.

 

 

As an aside, next time you use a holesaw in timber, do a shallow cut with the holesaw on the visible side before cutting the main hole ...

 

Yes I did remove the bleed screw before following Spring's advice. It worked fine but there's no way you can collect any of the water in a bowl as it just dribbles down the pipe. I used a towel. Thanks for the advice.

 

Those redundant holes were cut for a previous heater with pipes in different positions. They're all covered by the bottom of the water heater cover anyway so not visible.

Edited December 11, 2021 by blackrose

[Ex Brummie]

I always switch off the pump, open all taps, hot and cold, then disconnect the cold feed. Collecting the drainage is quite easy as a container can be placed underneath by moving the pipe a little. The hot tap needs to be open to relieve the vacuum it will hold. Disconnecting the cold feed is less restrictive than the drain screw so it empties more efficiently.