Water Heater Question

Geoffreykwright · August 14, 2019, 12:49:01 PM

Hi - I've got a slow leak in my freshwater system - every once and a while the water pump comes on and the bilge is slowly (very slowly) filling with clean water (like an inch a week). I've been able to isolate the problem to the hot water tank. For the time being I've bypassed the hot water tank - connecting the input hose and output hose (the way I would do when winterizing the engine. Leak seems to have stopped.

My question - is it safe to motor with the hot water tank bypassed? I am thinking it is, but I seem to recall something about the raw water which cools the engine coolant also passes through (around?) the hot water tank - that is how I get hot water when motoring I think.

Is it safe to motor with the hot water tank bypassed (well - safe except for the frustration of my wife not having hot water)?

Thanks in advance.

KWKloeber · August 14, 2019, 01:10:48 PM

No foul, no harm so long as they are tied together.

That's essential how the engine operates when it comes across the pond. Catalina takes the hose off and connects the WH.

Geoffreykwright · August 14, 2019, 02:17:20 PM

Thanks. So just to be clear - I'll be okay since the input and output hose of the water heater are connected? Its now a closed loop.

Now that I've bypassed the heater, no leaks and no occasional (but brief) running of the pump.

Just want to be sure no problem motoring.

Stu Jackson · August 14, 2019, 08:32:11 PM

That's correct, NO problem.

Ken is correct when he says the engines came without water heaters.

Why?

'Cuz they were (and are) tractor engines.

I get my Kubota parts from our tractor dealer about 3 km away from our house.

Great guys, right parts, fraction of the Universal prices.

Ken also contributed a very good wiki article on the coolant flow, with corrections to the manuals diagrams. You might be interested in checking it out.

Geoffreykwright · August 15, 2019, 08:33:52 AM

Thanks Stu, Ken...
...I'll try and find the wiki article.

Jim Hardesty · August 15, 2019, 09:22:19 AM

I would suggest when you replace your hot water heater install a bypass. Saves a lot of aggravation winterizing and is little added work when you have your water heater out. Here is a link to WM can probably do better someplace else.

https://www.westmarine.com/buy/camco--water-heater-bypass-winterizing-kit--329195

After looking closer I'd buy one with two 3way valves
Jim

KWKloeber · August 15, 2019, 10:25:25 AM

Geoff

The article, I think is the 2nd under the engine > cooling topic. I updated some text last night.

The camco kits Jim shows can be had from a discount RV place for about half the floating RV sources.
One consideration is to make sure you're getting a full flow ball valve. See pic for what you DON'T want.

I did an alternate method that assures full flow. (For unrelated reasons) I have my potable connection to the WH inzie/outzie on opposing male/female brass garden hose fittings. I simply unscrew them and screw together the m/fm hose ends. Even quicker would be brass garden hose quick connect fittings. I have great access to the WH (not buried in a cabinet) so my lack of C34 knowledge pontificating applies to if you have decent access somewhere so that you can easily access the hoses (doesn't need to be right at the WH.)

Geoffreykwright · August 15, 2019, 11:33:10 AM

Thanks. Bypassing the heater is pretty easy - I've got easy access to it and simply connect the 'in' and 'out' hose with a male-to-male barb. Takes only a minute or two...so I don't think I need to install something like this...but certainly would if the WH were not so accessible.

I'll have a look at the article.

Geoffreykwright · August 15, 2019, 11:38:55 AM

Ken - read the wiki - thanks - helpful. Next question - even though the water heater is bypassed, it will still get hot while under engine - correct? If so - any risk of it over-heating if there is no water in it?

KWKloeber · August 15, 2019, 01:10:24 PM

There's no issue running the system as you proposed. As I have said, no harm no foul.
HOWEVER, DO NOT turn on the shore power to the WH with no water in it. That can burn out the heating element.

Geoffreykwright · August 15, 2019, 01:16:47 PM

Yep - thanks - already thought of that and temporarily disconnected the WH breaker to prevent any accidental turning on.

Hugh17 · August 20, 2019, 02:55:45 AM

You can also bypass the water heater hoses at the engine/thermostat hosing by connecting a short piece of hose to the thermostat housing and engine. Picture on the left is my original M25XP showing the water heater hoses connected. Picture on the right is my replacement M25 with the water heater bypassed.

If your water heater is leaking and needs to be replaced then consider replacing those old hoses when you replace the water heater.

Stu Jackson · August 22, 2019, 04:23:15 PM

Quote from: Hugh17 on August 20, 2019, 02:55:45 AM
>>>>>>>>>>>>>>>>>>>>>>>>>>>>
If your water heater is leaking and needs to be replaced then consider replacing those old hoses when you replace the water heater.

Absolutely, writeup and link in Critical Upgrades.

Breakin Away · November 10, 2019, 08:33:58 PM

Quote from: Jim Hardesty on August 15, 2019, 09:22:19 AM
I would suggest when you replace your hot water heater install a bypass. Saves a lot of aggravation winterizing and is little added work when you have your water heater out. Here is a link to WM can probably do better someplace else.

https://www.westmarine.com/buy/camco--water-heater-bypass-winterizing-kit--329195

After looking closer I'd buy one with two 3way valves
Jim

Hi all, I'm re-activating this thread because it's relevant to me. I'm not replacing my water heater, but I am shopping around for bypass kits for my existing heater (which is only about 5 years old), and have a bunch of questions.

Does the linked Camco kit have the right threads for our heaters?
Will it fit in the tight confines of the MkII dinette settee? Is there an acceptable workaround with elbow fittings?
Is it possible to remove the old fittings and replace the new ones without removing the whole tank?
Is the three-way valve a "full flow" type? If not, can you recommend a valve that is?
I like the idea of a single three way valve paired with the check valve that's included for the hot water outlet. That simplifies things because you only have to flip one valve. But does this new check valve (in addition to the cold water check valve that's already present) create too much resistance to flow?
Finally, it appears that I'd have to add some hose barb fittings to attach the existing hoses. I wasn't able to pull apart my system today to measure the ID, but it looks like the hoses are about 3/8" id. Is this correct?

Jim Hardesty · November 11, 2019, 08:31:57 AM

By-pass is really simple. Here is what my by-pass looks like. I also put instructions in plastic on water heater in case someone else was doing it.

Instructions are on water heater as follows.

1. Turn off hot water ac breaker and water pressure dc breaker.
2. Turn cold water in (lower valve) to by-pass
3. Open tank drain
4. Open hot water at sink faucet. So tank will drain
5. To speed up draining use blow on vac or air compressor at sink faucet
6. Let tank drain
7. Turn hot water out (upper valve) to by-pass
8. Done

Jim