I've been doing research on the tankless on-demand propane hot water heater that is now being installed on Vegas & Axis RVs. I do not have this hot water heater in my 2015 Vegas; however, I wanted to ensure the revision I made to the Owners' Manual I compiled is correct regarding the operation of this Tankless Hot Water Heater.
Additionally, I've read in several threads on this forum owners complaining about the lack of hot water or luke warm hot water regarding this hot water heater.
In reading the owners' manual adjusting water temperature in this water heater is counter intuitive to everything we do in regulating the temperature of hot water at a tap. Basically conventional wisdom says regulate the temperature by adjusting the amount of COLD water being mixed at the tap. In terms of this tankless hot water heater -- that is EXACTLY the wrong way to adjust the temperature.
Here is what the Girard GSWH-1 says about the operation of their system and how to increase and/or decrease hot water temperature at the tap or shower head:
"The Girard Products model GSWH-1 is a new 'induced-draft', tankless water heater designed specifically for Recreation Vehicles (RV). Its configuration and size are consistent with the tank based RV water heaters currently in use and is designed for OEM's and after market use by the RV industry. A main feature of the GSWH-1 is a Dual BTU burner, which is set by the Mode Switch to either HIGH (34,000 BTUs) or LOW (27,000 BTUs). The incoming water temperature will raise 40°- 60° (F) based on water flow
A tankless water heater heats water while it is being used i.e., on demand. The output temperature of the water depends on the temperature of the inlet water AND the amount of hot water that is drawn
To operate, first purge air out of ALL hot and cold water lines, set the Power Switch to the ON position and set the Mode Switch to HIGH, then open the HOT Water Faucet by turning the faucet knob counter clockwise; the water will begin to heat up once the water in the piping has been purged.
DO NOT TURN ON THE COLD WATER
. Then DECREASE the flow of the water (turn the faucet knob clockwise) until you achieve the desired temperature
. The hot water valve behaves very much like a typical mixing valve: it INCREASES the temperature when the water flow is REDUCED. TO DECREASE THE WATER TEMPERATURE (i.e., make the water
cooler), increase the flow of the water by turning the faucet knob counter clockwise thereby increasing the flow
. DO NOT USE COLD WATER TO ADJUST THE TEMPERATURE
• The presence of a flow restrictor in the hot water line may limit your ability to reach a comfortable water temperature. For best results remove the restrictor in the shower head.
• Purge air out of ALL hot and cold water lines, including outside shower and wash machine water lines (if applicable). In a conventional installation the Girard Tankless Water Heater is connected to:
1. The RV's cold water system deriving its water input from a pressurized (45 psi or greater) source such as a shore connection or an RV water pump connected to the fresh water storage tank.
2. The RV's Hot water system (i.e. faucets and shower)
3. The RV's LP Gas system capable of supplying its rated BTU requirement.
4. The RV's 12VDC filtered electrical power distribution panel utilizing a 12 Volt, 10 amp fused line."
The highlighting and emphasis in the above description is mine. I wanted to show that adjusting hot water temperature is achieved by adjusting the flow from the HOT WATER valve -- not by mixing cold water by opening or closing the cold water valve.
Here is a link to the Girard manual: