[A/S] Re: RE: Hot Water On-Demand

[Stan Nicholson <stan@xxxxxxxxxxx>]

We decided to replace an early 8-or-so-year-old Precision Temp with 
another one when the old one developed a leak in the heat exchanger 
several months ago. It works wonderfully for the way we use the 
trailer. Here's our experience with pros & cons:

With full hookups, having unlimited showers etc. is a wonderful 
treat. The PT sits in the same location as the original tank heater, 
so it takes as long for hot water to travel through the lines to, 
say, the sink faucet for either kind of system. We've found no 
problem with the pressure switch sensitivity - if you listen 
carefully while opening the bathroom faucet (rear bath '72 
Overlander), you can hear the PT burner fire with the slightest water 
flow. The temperature rise has been more than satisfactory for every 
situation we've been in, although we haven't braved camping in 
sub-freezing weather yet.

When dry camping, it takes time for hot water to get to any outlet, 
so there's an impact on grey water storage whether you're using a PT 
or tank. The only relative disadvantage of the PT occurs when you're 
trying to conserve water by turning the hot on and off for small but 
frequent amounts. In a few seconds you get hot water, then shut it 
off for a few seconds, and then turn it on again. You get tepid water 
and the PT burner fires up, and within a few seconds you get hot 
water again. With this pattern of hot water useage, the temperature 
isn't stable. In short, the PT works optimally with stable demand, 
which doesn't always fit the boondocking limits on fresh water 
supplies and grey water storage. In our experience, however, this 
hasn't been a big enough drawback to make us want to give up the PT. 
That's why we elected to stay with that technology.

Stan