Winterising pressurised fresh water system

[MagicalArmchair]

I have never winterised a fresh water system before, from what I can see, I suppose:

• Run the hot tap until dry the empty the tank, the pump will still run even after the water has run out, so then turn it off at the switch.
• Drain down the hot water header tank (Err, not sure how to do this, take the pipe off the bottom?)
• Drain down the hot water holding tank (Err, not sure how to do this either, again, take the pipe off the bottom of the tank?)

Can anyone impart some useful advice please? Photos of the system are below...

 

[pvb]

Yes, empty the tank. Drain the calorifier (there may be a tap on the bottom). The "header tank" you referred to is a pressure accumulator and you needn't touch it.

However, if your boat is staying afloat, this may not be necessary. My boat stays afloat all winter and I just switch off the water pump then open the taps in galley and heads, so they don't get damaged by ice expansion if it freezes.

 

[MagicalArmchair]

Thanks pvb, is the calorifier the red one?? She is out of the water for the winter, so worth doing!

Edit: Ah, no, I see the calorifier is the blue one, awesome, nice and easy.: http://www.asap-supplies.com/green/marine-water-heaters/hotpot-accumulator-and-expansion-tank-520605

 

[old_salt]

You can get an antifreeze treatment for fresh/drinking water systems usually from caravan shops.

 

[Cloven]

What I do is as follows:

1. Run the system dry using the pump through both hot & cold taps (I actually have a single mixer tap but I open both hot & cold switches)
2. Remove both tap heads (mine screw on) in case any residual water remains
3. Remove the inlet and outlet pipes from the pump and then run the pump for second or two just to clear any residual water. Also allows me to clean out the fresh water filter which is attached to the pump. I note from your pics that you have one attached to your pump.

Calorifier - you may be lucky and have a lower drain point and/or an upper bleed point. I don't so what I do is:

4. Remove the cold water supply pipe at the bottom of the calorifier - very little water comes out at this stage
5. Place a bucket under the now opened inlet and then crack open a fitting in the upper hot water outlet. This allows water to drain freely from the calorifier into the bucket. I have removable push-fit fittings so it is easy just to unscrew one of these.

My calorifier holds about 2+ buckets. Once a bucket is nearly full, if you close the upper outlet as in 5 above, then little water will come out as you either empty the first bucket or swap if for a second bucket.

6. Once drained, you can then either reconnect all the opened fittings (pump, taps & calorifier) or what I do is leave them open in case any residual water freezes but make a note to reconnect them at the start of the next season. Forgot to do this one year and wondered why when filling the system it would not repressurise. Then I found rather a lot of fresh water in the bilge - you only do that once!!

Hope this helps

 

[Bav34]

All three taps on until the water tank and calorifier are empty. Always have them in a 'warm' setting so that both hot and cold pipes drain.

Turn off water pump.

Leave galley tap open.

Take heads and bathing platform shower heads off.

That's it.

I'm sure that someone will come up with a reason why I should, but I never drain the calorifier more than has been achieved by the above action. Of course there is some residual water in the bottom but this has a large area to expand in should it ever get that cold.

 

[Cloven]

All three taps on until the water tank and calorifier are empty. Always have them in a 'warm' setting so that both hot and cold pipes drain.

Turn off water pump.

Leave galley tap open.

Take heads and bathing platform shower heads off.

That's it.

I'm sure that someone will come up with a reason why I should, but I never drain the calorifier more than has been achieved by the above action. Of course there is some residual water in the bottom but this has a large area to expand in should it ever get that cold.

Maybe just my system, but if I do what you suggest above, the calorifier is still completely full even after the pump has apparently drained all water out of the system, hence my regime in #5 above. Reason I know is that I did as you suggest first year I had the boat and friend suggested I check the calorifier - it was full!!

 

[prv]

make a note to reconnect them at the start of the next season

I take out the fuse from the water pump circuit so that I can't absent-mindedly flip it on and spray water everywhere from dismantled fittings.

Pete

 

[Phoenix of Hamble]

The calorifier can retain a significant amount of water unless you take the time to drain it as well... once the pump has stopped due to lack of water in the tank, there is nothing to clear the calorifier... mine holds pretty much all of its content unless drained specifically. Somone posted a picture on here a while back of a calorifier split by freezing water, but can't find it at the moment.

 

[Bav34]

The calorifier can retain a significant amount of water unless you take the time to drain it as well... once the pump has stopped due to lack of water in the tank, there is nothing to clear the calorifier... mine holds pretty much all of its content unless drained specifically. Somone posted a picture on here a while back of a calorifier split by freezing water, but can't find it at the moment.

Understood.

You can see how low my take-off point is so it comes down to individual design.

 

[Phoenix of Hamble]

That's interesting, is that your take off point at the bottom with the PRV on the fitting?... its normally at the top to take off the hot water, rather than the cold that is replacing it, that will naturally sink below the hot water.

 

[prv]

You can see how low my take-off point is so it comes down to individual design.

The take-off hose is the red one at the top!

Pete

 

[Phoenix of Hamble]

The take-off hose is the red one at the top!

Pete

That's what I thought when I looked at the pic too, in which case, the calorifier will remain full until manually drained.

 

[Bav34]

That is interesting. I had cause to remove the element once and the amount of water that flowed out certainly didn't reflect a full tank. I guess the forward slope of the tank causes a lot of water to drain ... I'm trying to visualise it now ... probably a third comes out of the red pipe which certainly give a lot of expansion room.

Given the lagging and proximity to the sea I don't see a problem but I guess all boats are different.

As an aside, the top fitting was a temporary fix ... whilst taking out the element I unknowingly knocked the hot water pipe out of its retaining clip further forward. Over several seasons of the weight being taken by the pipe it developed a crack ... all quickly repaired by a freshwater tap fitting pending finding the correct part. In Brittany :sleeping:

 

[pvb]

Typically, the hot water outlet pipe is bent up inside the calorifier, so that it draws the hot water from the top of the tank. This also enables the air in the tank to be removed, maximising the volume of water.

 

[Cloven]

Typically, the hot water outlet pipe is bent up inside the calorifier, so that it draws the hot water from the top of the tank. This also enables the air in the tank to be removed, maximising the volume of water.

Interesting pic - thanks. Explains why on some calorifiers the hot water outtake does not appear to be right at the top.

 

[Phoenix of Hamble]

Given the lagging and proximity to the sea I don't see a problem but I guess all boats are different.

I rarely bother to drain my calorifier down if I am staying in the water over winter... the combination of sea temperatures, plus a frost guard heater, leaves me little to worry about... so suspect you're right!

 

[pyrojames]

I now take the approach that it is better to keep the boat above freezing with heater on board all the time. The cost is not high compared to the cost fixing bits and pieces that have frozen.

 

[prv]

This is the first year I've bothered draining Ariam's calorifier - it's the first time we've wintered ashore rather than laid up afloat. But I found ice on the decks even at midday on Saturday, so it seemed like a good idea.

This calorifier has the hot takeoff at the top, so no internal bent tube needed.

Pete

 

[prv]

I now take the approach that it is better to keep the boat above freezing with heater on board all the time. The cost is not high compared to the cost fixing bits and pieces that have frozen.

Does require power in the yard, though, which we don't have.

Pete