Hot water & foot pump?

[Brewgyver]

Ottow, tank-type water heaters have to be kept 100% filled with water. If the heating element is not completely immersed when energized, it will overheat and quickly burn out. In order to have a water heater in a non-pressurized system, you have to design it with that in mind. To accomplish this, you'd have to have the water heater as the lowest point in the system, even when heeled over.

IMHO, water conservation is not at all dependent on HOW the water gets to the faucet, but WHO is using the faucet.

[Brewgyver]

Originally Posted by stormalong

You keep it full. Pumping in the cold water pushes out the hot water. Filling the tank is a one time job. Think of it just like a pressure system with manually developed pressure. No need for a hot water rated foot pump.

This would be a good alternative. You'd want to have to include a good check valve, and not rely on the one in the foot pump.
Personally, I prefer pressurized.

[Brewgyver]

Originally Posted by ottow

... I know I need a mixing valve as the water may be 70-90C in the heater and that needs to come down to about 50-60C to be anywhere near safe but will a foot pump handle water of that temperature?

Electric water heaters have thermostats. While you could add a mixing valve, it would be safer to just set the heater thermostat at a safe setting. BTW, that should be NOT OVER 50 C (122 F). 60 C (140 F) can cause scalding in seconds. Most domestic water heaters will not go over 65 C (150 F).

[jamhass]

Originally Posted by Brewgyver

Electric water heaters have thermostats. While you could add a mixing valve, it would be safer to just set the heater thermostat at a safe setting. BTW, that should be NOT OVER 50 C (122 F). 60 C (140 F) can cause scalding in seconds. Most domestic water heaters will not go over 65 C (150 F).

True,but ...

Most marine water heaters are also heated using engine coolant, and the hot water can get close to the engine coolant temp, on the order of 180 F.

Also, check with Whale or other manufacturers directly re temp limits.

[Nicholson58]

Originally Posted by jamhass

True,but ...

Most marine water heaters are also heated using engine coolant, and the hot water can get close to the engine coolant temp, on the order of 180 F.

Also, check with Whale or other manufacturers directly re temp limits.

Spot on true. Care is always in order. Also of note, if your thermostat on the engine fails you can boil the water heater. Did it. Lost all of our 280 gallons of fresh water. It was a raucous motor sail transit leaving Bonaire to Puerto Rico. Didn’t notice the loss until it was time to flush a head. The temp-pres relief valve failed open a crack. These are Home Depot $15. Bought a spare. Also, we turn off the pressure water under way now. Each lesson is an unforgettable hard whack. Found a nice marina near a hardware, free water. Replaced the thermostat. Loss of pressure water may have kept the engine cool while it was leaking. I could see high temp and shut down until we needed to dock.

[Jim Cate]

fwiw: we use foot pumps at both sinks, cold water only. We do have a pressure pump which supplies water to a propane flash heater for the shower and to the shower on the sugar scoop... and nothing else. For dishwashing, we heat enough water in a kettle to do the job, then rinse in ambient water from the foot pump.

All this is second nature to us... been doing it for a long time, and it makes controlling water usage very easy. We get around 5 weeks from each of out 400 L tanks without feeling that we are skimping. YMMV... and from some of the "we need 100 L a day" comments that appear here, that mileage can vary a LOT!

Jim

[Nicholson58]

Ok, I give. Grandma and I are sequentially sitting our various grandchildren. This month, 2 and 4 year olds. Parents left this morning. The little one just projectile blew pizza across the living room and down his front. Goo on the rugs. We are just glad the older one did not sympathetically hurl. So glad to be in a house with hot running water, soap, bleach, washing machine. I’m heading for a hot shower.

[kev_rm]

Originally Posted by GordMay

That seems to be the prevailing attitude.
However, as a general rule, everything that has had direct contact with food should be cleaned, and sanitized, especially if in contact with uncooked food.

i know exactly zero people who sanitize their dishes. I realize governments have established standards for commercial operations- i just don't think anyone outside of that arena does it and so far people are surviving.

[Brewgyver]

Originally Posted by kev_rm

i know exactly zero people who sanitize their dishes. I realize governments have established standards for commercial operations- i just don't think anyone outside of that arena does it and so far people are surviving.

You probably do know lots of people who sanitize their dishes. They use modern electric dishwashers. And by modern I mean made in the last 30 years or so, and since they rarely last more than ten years...

[CF32907]

Originally Posted by Fransw

Ambient temp water and proper soap worked for me on any adventure trip for the last 20 years..
But it also depends on your diet. For example animal fat is not easy to clean with cold water but still doable. Its more about the soap imo..

Rather use the hot water/energy to wash yourself!

Capt.VR here, I agree, completely. I had a 65' schooner "Altair" Three adults and one child. Sailed from Windwards to Florida a number of times over a five year period. Only solar heat for showers, water very rarely over 100 degrees. No infections no sickness ever. Cloths washing, my washer was a five gallon pail, with snap on lid with probably 40 2" holes drilled sporadically around it. Put your clothes in it, snap the lid, throw it in the water, drag it behind the boat at 7 knots for 15 minutes, haul it out rinse cloths in fresh water, dry on life lines. Again, no infections, no rashes no problem, very simple. Dishes were all washed with sea water and Joy liquid, rinsed with fresh from our spray jug. Again, no sicknesses of any type.
Number one, no water heater heats to 170 even in a house, most WH are set for 105 to 120, much more than that you will scald yourself. For your second problem, no type of vinyl tubing will work, you will need CPVC, the yellow PVC. Another reason for not using vinyl is the hot water will release the BPA. The last, as far as I know, all foot pumps are rubber diaphragm type, The rubber will not cope with the hot water.
With cruising for most of my life, and the 100's of cruisers that I new, virtually no one had spacific water heaters. Most had home made solar systems or the hanging bags. Personally, we mainly used a 2 gallon pump jug. Showers, washing, dishes, cleaning fish, it was 90% of our washing and rinsing duties. Cheap, water frugal, easy to use, with using it ever day, one lasted three years before we replaced it.... Capt. Vince Rakstis, Ret.

[CF32907]

Originally Posted by stormalong

Why not use the foot pump to push water into the water heater? The same as a pressure water system does.

CaptVR here, I've built 6 boats, refurbished / rebuilt a 100 or more over 50 years. I've ran miles of plumbing, and your Idea floored me. I'm a very knowledgeable boat builder, marine surveyor. I cannot believe I never thought of that. I have used air pressure on a few occasions on small boats with a five gallon tank, but never thought of just for hot water at a single fixture. With doing this, you could use a foot pump for supplying water to the WH and pushing the hot water through.
Very good Sir, If your ever in St.Petersburg, I'll buy you a Capt. and coke.
Capt. Vince Raksris, Ret.

[stormalong]

Originally Posted by CF32907

CaptVR here, I've built 6 boats, refurbished / rebuilt a 100 or more over 50 years. I've ran miles of plumbing, and your Idea floored me. I'm a very knowledgeable boat builder, marine surveyor. I cannot believe I never thought of that. I have used air pressure on a few occasions on small boats with a five gallon tank, but never thought of just for hot water at a single fixture. With doing this, you could use a foot pump for supplying water to the WH and pushing the hot water through.
Very good Sir, If your ever in St.Petersburg, I'll buy you a Capt. and coke.
Capt. Vince Raksris, Ret.

Vince, Thanks for the response. I don't get to Florida these days. Except for Canada and Alaska I think my cruising days are over (for now). Being in Washington state I am about as far away as you can get and still be in the continental U.S.

With my next G & T I will raise my glass to you.

Brian

[ottow]

Originally Posted by stormalong

Why not use the foot pump to push water into the water heater? The same as a pressure water system does.

Very good idea, I might actually do this assuming I can figure out a way to mount the calorifier lower than the water tank. I suspect this may be almost impossible in my boat but I'll see.


Thanks!

[stormalong]

Originally Posted by ottow

Very good idea, I might actually do this assuming I can figure out a way to mount the calorifier lower than the water tank. I suspect this may be almost impossible in my boat but I'll see.


Thanks!

Why does the calorifier (water heater) need to be lower that the water tank? As long as you can pump water into the calorifier the foot pump pressure can pump the hot water out. The one downside of any calorifier is the wasted water in the piping that has to be forced out before you get the hot water. I suppose if you are really wanting to save every drop of water you could collect that water in a pitcher. Or you could use a small diameter hose from the calorifier to the spigot to minimize waste.

[ottow]

As pointed out by someone earlier in this thread, a foot pump is not 100% leak-proof, so if the calorifier is higher than the water tank, it can drain back into the water tank thru the pump.
This would be bad for efficiency, bad for any electric heating element which may become uncovered and bad in general for the water tank which potentially will end up luke-warm, thus promoting growth there.