Hot Water Tank Bypass - Maxum Boat Owners Club

tackleshep · 08-02-2010, 02:16 AM

Ok, one last question for you guys familar with Maxum's systems. My hot water tank is basically worthless, smells like crap and when you dock within 25 yards of a shower house we just won't use it. I want to winterize it and shut her down for good, but I can't find a bypass for it, would that be standard or will I have to create one?

rtw_ca · 09-09-2010, 03:37 AM

There are bypass kits available at most marine suppliers. It's really just 2 - T-valves and a short piece of tubing.

I have a 3000SCR and I love having the hot water tank. It's nice to wash dishes in warm water and even wash your face and hands before bed! You might want to investigate why yours smells so badly. Does your cold water smell? If not then the problem is certainly localised in the hot water tank. Perhaps you've got some bacterial growth going on in there. There are products available for that too!

Good luck.

Richard

tackleshep · 09-10-2010, 03:40 PM

Richard,

The main problem with my hot water tank is lack of use. It is very common in these parts where they are not used on a regular basis. It can easily be fixed my mixing in some vinegar and cleaning it good but then it would need regular use to keep it from happening again. This just wont happen for us. We are on an inland lake and the boat stays at the same Marina every night. I am a 30 second walk from shower houses specifically for us slip holders. I also have a coffee pot we use to heat the water to wash dishes. The simple fact is we had the boat for two months before I even tried to use it and it was for dishes. So I couldn't blame anybody for using their especially if I was in open water and taking trips but for us, hell our electrical lines stay mounted on the dock and don't even go with us....if that gives you an idea of what were all about.

shrew · 09-10-2010, 09:34 PM

This is actually pretty easy. The biggest question you have to ask yourself is; "Do I want Cold water to come out of the hot tap?", or "Do I want no water to come of the the hot side and only water to come out of the cold tap?".

The idea is the tank plumbs to the pressure water pump. The pressure water pump should plumb to the cold water side. there should be a couple of T-connectors downstream of the pump. One for each cold water tap and one for the hotwater heater. So you have a couple of options here.

Cold water from both taps: Disconnect the cold water in line and the hot water out line from the hot water heater. Connect the cold water IN line to the hotwater OUT line, bypassing heater. This will treat the hot water taps like cold water taps. If you remove the hot water heater completely, the plumbing will be a bit ugly.

No Water From Hot Water Taps: Trace the cold water in line from the hot water heater back to the pressure water pump. You will find a T connector which feeds the hotwater heater. Remove the T connector and replace with an inline connector. Now the inline connector will go from the pressure pump to the cold water side without splitting the cold water for the hot water heater in any more. If you do this, I would get terminators for the hot water side. If the system is left open, mold will grow like crazy inside the lines. If you ever do decide to install a hot water heater, it will be a bit nasty.

Either way the entire process should be cheap and should be fairly quick to complete. I replumbed my entire pressure water system two seasons ago. I replaced the pex tubing as well as every connector in the boat.

BTW- If the RV store tries to sell you a bypass kit, it will most likely be incomplete. I bought one for winterization purposes and either it was missing a second shutoff switch or it was missing a check valve. It would be cheaper to do it yourself.

Take a look at these:

http://www.seatechinc.com/Products

I bought mine at an RV center for a bit less than the marine supply stores are charging. I had the old compression style and as a result of the PO failing to winterize properly, many were beginning to fail. The guy at the RV store even looked skeptical, saying "I'm not sure if you can use these on a boat". When he handed me the parts, I held up the label and said "The manufacturer is SeaTech, inc......how many RV's do sell for use in the Sea? I wonder if these would work on an RV?" LOL (Parts guy blushed and said "I never noticed that before").

tackleshep · 09-11-2010, 02:43 AM

Thanks Shrew,

Yeah my plan is to flush, clean, and drain the hot water tank to leave it dry and clean to prevent any future damage. My goal is to disconnect but not remove or keep it from being used in the future. Plan is to bypass it where if I wanted to commission it again or sell the boat it could be fired back up without any problems.

Tommyfmu · 09-11-2010, 04:27 PM

tackle, if I were you (and I'm going to do it this weekend) install two three way valves so the hot water input will divert, through a short tube, straight to a three way valve coming off of the hot water out on the hot water heater. That way in order to commission the hot water heater again for demo purposes upon selling it, all you have to do it throw two valves and it's in use again. I'm doing this because in winterizing, it takes an extra 11 gallons of non tox antifreeze to fill the hot water heater, whereas if it's completely emptied now with bypass valves that saves using the nontox.