Hot water heater by pass on SO 389

[Chris Meyer]

Curious if anyone has added a hot water heater bypass on SO 389.

It is a Nautic Boiler.

Looks like hot water output is at the top and cold water input is at the bottom next to the dump valve.

Attachments:

Nautic Hot Water Heater.pdf (115.72 KB)

[jlasail]

I have a SO409, most likely a similar set up as yours. I can’t open your attachment but I confirm that hot water egress is on top of the tank. I insert a bypass made out of a combination of quick connectors ( they must be a specific name for it) for winterization by connecting the egress and ingress pipes of the tank. Not sure it answers your question.
Jl

[Chris Meyer]

Thanks.
Sorry about the attachment.  I have tried in the past to follow the directions for attachments and with no luck.
I bought a bypass kit from CAMCO which has two diverter valves and a shunt hose.   I had this last time and it worked well.
Just didn't know if there is a better way to do this.   Hot water egress is at the top and cold water input is at the bottom.  The the valve on the top should be no problem.    The cold water input will be harder to access!

[ForGrinsToo]

The Quick Nautic "boiler" on the US-built 36i has a tee on the (bottom) cold water inlet which splits flow to a mixing valve on the outlet. The mixing valve allows "cold" water to bypass the boiler then mix with the hot so that a maximum safe temperature is not exceeded in the hot water line. All of that is hard-plumbed with threaded fittings, PTFE tape, etc. Quick disconnects are downstream from the mixing valve (roughly a 2' or 60 cm stub) and upstream from the boiler (roughly a 1' or 30 cm stub).

Quick has a kit with mixing valve that can be added to any of their water heaters.
www.quickusastore.com/boat-supply/water-heaters/spare-parts/thermostatic-mixing-valve-kit/

In other postings, there has been discussion of that mixing valve sticking (failing to mix). Most find the valve difficult to adjust - and don't want to risk breaking it by adding leverage.

For winterizing, I separate the two quick disconnects to isolate the tank, and let the tank drain to the bilge. I clamp a piece of PVC tubing to the supply line and to the hot water line so that I can pump antifreeze through everything but the tank.

Hope this helps.

Geoff

[Chris Meyer]

Thank you, Geoff.

I will look for the quick disconnects.  Didn't see them.

[Chris Meyer]

Aug 4, 2020 20:20:36 GMT ForGrinsToo said:

The Quick Nautic "boiler" on the US-built 36i has a tee on the (bottom) cold water inlet which splits flow to a mixing valve on the outlet. The mixing valve allows "cold" water to bypass the boiler then mix with the hot so that a maximum safe temperature is not exceeded in the hot water line. All of that is hard-plumbed with threaded fittings, PTFE tape, etc. Quick disconnects are downstream from the mixing valve (roughly a 2' or 60 cm stub) and upstream from the boiler (roughly a 1' or 30 cm stub).

Quick has a kit with mixing valve that can be added to any of their water heaters.
www.quickusastore.com/boat-supply/water-heaters/spare-parts/thermostatic-mixing-valve-kit/

In other postings, there has been discussion of that mixing valve sticking (failing to mix). Most find the valve difficult to adjust - and don't want to risk breaking it by adding leverage.

For winterizing, I separate the two quick disconnects to isolate the tank, and let the tank drain to the bilge. I clamp a piece of PVC tubing to the supply line and to the hot water line so that I can pump antifreeze through everything but the tank.

Hope this helps.

Geoff

Hi Geoff,   I  found  the two disconnects.   Do I need to plug these when I disconnect or  do they seal when I disconnect?

I did understand your last comment "clamp a piece of PVC tubing to the supply line and to the hot water line".   If i disconnect the hot and cold lines and put anti freeze in the water tank, won't it pump thru all lines just fine?

[ForGrinsToo]

Hi Chris,

With our Quick Nautic "boiler" the two stubs (in and out) terminate in a female quick disconnect. Press the ring to allow the male coupling from the tee to disengage from the female, leaving a male projection that is 3/8 to 1/2" o.d. Same for the outlet, where one branch goes to the sink and the other makes its way to the head.

I clamp a short piece of 3/8 or 1/2 i.d. PVC tubing between the two male projections to bypass the tank, then pump antifreeze from a water tank through both hot and cold lines all the way to the stern shower (end of the line). I normally leave the lines filled for winter, then flush with fresh water via the water tanks when de-winterizing.

The male run tees don't have an internal check valve. I don't know about the female, but given how slowly the boiler drains, there could be a backflow check valve somewhere.

Depending on the model, you'll have at least 6 gal (23 L) of water to drain from the boiler. Some would say, as long as there is room for expansion, it doesn't have to be empty. But you don't want the ice formation to damage the electric heating element. Adding antifreeze to the boiler, assuming it is 6 gallons, you need probably 12 gallons to flush through before you bring the antifreeze to full strength. So far more cost-effective to drain it. I let it dribble overnight into the bilge before pumping out the bilge and refilling with antifreeze.

Fair warning: while I typically add about a tablespoon of bleach to a freshwater tank while filling, if the pink polypropylene glycol antifreeze remains it will react to create a foul taste. So I flush at least three times with increasing volumes of water before the final fill.

All that said, it would be really nice if I could just turn a valve or two and bypass the boiler, but I still need to drain it.

Geoff

[Chris Meyer]

Thank you, Geoff!

I could follow everything you wrote.  Very kind of you to share your knowledge.

On my Beneteau 321, I installed a couple valves and could bypass the tank in about 5 seconds and it worked well.

I was pleased to find to quick disconnect couplings!

Chris

[moonshadow]

Simple question here. Is the reason to bypass the water heater only to avoid using a lot of antifreeze in the winter and the water flushing to clear all that out in the spring? Or are there more reasons?

[Chris Meyer]

Yes.  That at least is my motivation.

[Chris Meyer]

Aug 5, 2020 21:16:56 GMT ForGrinsToo said:

Hi Chris,

With our Quick Nautic "boiler" the two stubs (in and out) terminate in a female quick disconnect. Press the ring to allow the male coupling from the tee to disengage from the female, leaving a male projection that is 3/8 to 1/2" o.d. Same for the outlet, where one branch goes to the sink and the other makes its way to the head.

I clamp a short piece of 3/8 or 1/2 i.d. PVC tubing between the two male projections to bypass the tank, then pump antifreeze from a water tank through both hot and cold lines all the way to the stern shower (end of the line). I normally leave the lines filled for winter, then flush with fresh water via the water tanks when de-winterizing.

The male run tees don't have an internal check valve. I don't know about the female, but given how slowly the boiler drains, there could be a backflow check valve somewhere.

Depending on the model, you'll have at least 6 gal (23 L) of water to drain from the boiler. Some would say, as long as there is room for expansion, it doesn't have to be empty. But you don't want the ice formation to damage the electric heating element. Adding antifreeze to the boiler, assuming it is 6 gallons, you need probably 12 gallons to flush through before you bring the antifreeze to full strength. So far more cost-effective to drain it. I let it dribble overnight into the bilge before pumping out the bilge and refilling with antifreeze.

Fair warning: while I typically add about a tablespoon of bleach to a freshwater tank while filling, if the pink polypropylene glycol antifreeze remains it will react to create a foul taste. So I flush at least three times with increasing volumes of water before the final fill.

All that said, it would be really nice if I could just turn a valve or two and bypass the boiler, but I still need to drain it.

Geoff

One more question about the hot water heater....

I wanted to drain it now since there was some anti freeze in it from the commissioning.
I found the pressure relief valve, but there is no "dump valve".

The only way I can see to drain the hot water tank is to remove the cold water input line (quick  disconnect) and let it drain in the bilge.   Seems odd there is no better way.

Am I missing something?

[ForGrinsToo]

What I do is disconnect the supply line then open the overpressure relief valve to allow air to enter, and the contents of the tank (about 6 gal?) to drain to the bilge.

[Chris Meyer]

Thanks Geoff.   Was hoping there was an easier solution!