Help with winterizing Isotemp water heater

[DougM]

I'm trying to winterize a water system with an isotemp water heater on my new boat (first time). The water heater has a themal mixing valve system on it, as per photo. There are valves on the inlet and outlet

The valve on one side turns 1.4 turn CCW and puts it in drain mode (inlet side i think). There is a valve on the other side (outlet i think). There is a flex hose connecting the two. The manual does not seem to say what closing the 2nd valve does.

I'm hoping that operating both valves puts it in bypass mode maybe, i hope. Either way i need to figure out how to clear out flexhose between the valves.

I'm going to blow the system out with 20psi air, wondering which way to leave the valves over winter

Anybody familiar with these? Would appreciate any advice.

Doug

[DougM]

nobody knows anything? I know it is boring but ...
d

[tkeithlu]

Have you got a lowest point valve for the entire freshwater system? If not, can you make one? Then open the top outlets (shower, sinks) to let air in and the bottom one to let water out. Drain the tanks and the heads.

Most water heaters have a low point valve. If not, take out the low electric heating coil.

[ggray]

I have an Isotemp water heater, perhaps an older model but still relevant.

I assume your drawing is turned sodeways, and the bottom is to the left? If so opening the valve at the center left (the bottom) will drain the tank.

But there should also be a small machine screw in the mixer valve that needs to be removed to let the small bit of water there drain out.

If you can blow all the water lines clear of water, great! I never have, so pump the pink stuff through. I installed a bypass line around the water heater to fill the hot water lines w/ pink stuff

[rphdiego]

If you use the pink stuff make sure you completely flush it all out of the water heater before using it again or your hot water will always have a smell to it and might be a bit foamy.

[Scrimshaw4]

Turn off water pump.
Drain the fresh water from the water tank.
Leave the drain valve open for the winter.
Disconnect the freshwater inlet and outlet from the water heater.
Using a short piece of hose, connectors and clamps reconnect the the inlet and outlet hoses together. This provides a fresh water bypass from the tank.
The idea is to not allow any water system antifreeze into the water tank. It leaves an odor for a while when the tank is heated.
Turn water pump on to check for leaks and then antifreeze all your water lines and spigots.
In the spring fully flush the anti freeze from your all your lines completely before you reconnect the lines to the water tank.
Remember to close the drain valve.
Put the bypass hose and connectors away for use the following winter.
PS: A little baking soda in the water tank after you flush the antifreeze will help "sweeten" the water.

[JussiM]

I have an Isotemp water heater. I have winterized the boat when needed. The Isotemp manual is quite clear about how this is done - do you have a manual available? If not, manuals are found in the Net. The procedure may depend on the specific model.

[DougM]

Thanks for all the replies.

The water tank is mounted vertically, the diagram shows the bottom of the tank as installed.

The isotemp manual does say how to drain (turn the knob 1/2 ccw) but doesn't say anything aobut hte thermostatic mixer line .. wondering if stuff gets caught in there.

I can't get to one to the darn fittings so bypass is not an optoin this year, and i'm out of time so i will push pink antifreeze throught the cold water circuit, the pump a little into the drained hot water tank, then blow it all. And cross my fingers.

Next year I think i'll be installing bypass with valves.

d

[George DuBose]

Gee, I was only draining the hot water tank, leaving the output hose disconnected. I run the freshwater pump to empty the hoses. Drain my water storage tanks. That's it.

The hot water hoses from the engine to the Isotherm and back to the engine have antifreeze in them anyway.

Boat has wintered outdoors on land in The Netherlands and has even spent a winter in the ice.

I do put antifreeze in my toilet and lines related to it.

When I was concerned about water freezing in my bilge over the winter due to a slow leak (now repaired) I took a 4" diameter piece of flexible round aluminum pipe, wrapped it with a gutter-heating cable and tied the cable all along the output hose of the bilge pump and left it plugged in all winter. The gutter heating cable has a thermostat. This kept the pump from freezing and ice forming in the bilge.

[ggray]

Originally Posted by DougM

Thanks for all the replies.

The water tank is mounted vertically, the diagram shows the bottom of the tank as installed.

This drawing looks like perhaps a newer model than mine, so you may be ok, but I would check w/ Isotemp about the installation.

On mine, the brackets are strapped to the tank such that the tank can be rotated w/ respect to the base, so that the drain is at the bottom. Is your drain at the bottom of the tank?