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Re: Mystery thermostat question

Reply #25 – December 30, 2016, 06:12:55 pm

All, very much appreciated.

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Re: Mystery thermostat question

Reply #26 – December 30, 2016, 08:55:06 pm

Rudy posted here my same experience.  Up to the 1.5 gpm you will receive a 55 degree temp rise on the hot water side over the input water temp.  Meaning the storage tank or input water hose temp.

If you want hotter hot water up to the mixing valves setting start with warmer tank or water in temp.

Search rudys posts you will see his comment about this observation.

If I start with warmer water then the wall mounted shower temp adjuster can be adjusted more towards the cold side as the hot water input is hotter.

If the input is 32 degrees you will get 87 at continious rated flow of 1.5gpm

At 70 degree input temp you get 125 degree continious 1.5 gpm.

You may get more temp rise in short spurts but what I was testing was continious output. 

Once the copper plumbing around the burner can stored hot water is depleted then the burners max output results in a 55 degree temp rise over the sources temp.

The oasis unit offers 60 degree rise at 3.0 gpm.  Designed for two showers on at the same time.  Bath and a half coaches.

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Re: Mystery thermostat question

Reply #27 – December 30, 2016, 10:20:08 pm

"If you want hotter hot water up to the mixing valves setting start with warmer tank or water in temp."

You will need to explain this to us. The aquahot heating element whether electric or diesel will shut off at a set temp. The water in the tank [coils] will be this temp. If the flow is such that the aquahot can maintain that temp, it will stay at that temp. If the aquahot can transfer enough heat to the water flowing into it, the temp will remain the same and not get any hotter than the temp of the coolant. The water in temp only comes into play when the aquahot coolant cannot transfer enough heat to the water used.
The water in your fw tank may be only 40 f. but if the flow of water through the heat exchanger is slow enough, the hot water coming out of your faucet will be max. temp. Easy  to demonstrate. When your fw tank temp is 40 f., turn your shower and sink faucets on full, water will start out at full temp and then start to drop because the aquahot is not keeping up. Now just open up the sink at low flow, the temp will remain at full temp because the aquahot can transfer enough to keep the temp at the max set by the mixing valve.
So you see it is not so much about the water in temp, but about how much water you are trying to heat.
55 f. rise at 1.5 gpm is possibly equal to 75 f. rise at .5 gpm.
Hotter water in does not necessarily mean hotter water out.

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Re: Mystery thermostat question

Reply #28 – December 31, 2016, 01:43:10 am

If you operate the unit continiously like it's rated for you will finally run into the units 55 degree rise at 1.5gpm over the inlet supplies temperature.

Anyone disagree that that's the units design limits?

You may never run into it a motorhome but you could run a hose into the coach and attach a hose to the outside faucet and with the hose and diesel burner on and the hot water side of the faucet open to the ground you will finally have 55 degrees difference between the inlet hose water temp and what comes out of the tap, 

Somewhere in the flow the burner will come on and extra residual heat retained in the boiler will be used up and the burners actual btu input will be the waters sole heating source.

55k btus into a continious running system is designed to heat 1.5 gpm to a 55 degree rise over inlet temperature.

So in a continiously operating system the inlet water temp variations will be reflected in the output water temp.

Not sure of the coils around the boilers capacity or the aluminum/steel boilers ability to retain heat but over long enough you will reduce its heat retention enough to eliminate its influence.

After that its the straight btu input minus the plumbing systems hest loss getting to the faucet.

Straight technical test.  Not normal world.

If I wanted to provide showers externally to a crowd the unit is capable of a continious 55 degree rise over the input water temp.

32 degree water would give 87 degree cold showers.  Not a good winter continious hot water provider.

A electrically heated water hose into the coach should warm the water enough to provide continious showers if so desired.

We are sort of preppers and I want to know the units real potential.

You could potentially furnish showers to a large group if the water in was 50 degrees or more continiously.

Not important.  I test things most could care less about or ever use things this way.

Good test to see if your coils are loaded with lime and sediment like most are.

Rudy talked about cycling five gallons of vinegar through the coils to flush the line and sediments.

Good test would you think?

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