
| Authors | Nick Turman-Bryant Justine Cook |
|---|---|
| Location | Arcata, California |
This is the Operation and Maintenance (O&M) manual for HEIF CCAT solar hot water system. Also check out the CCAT Data Collection/OM for more information on the dataloggers. Please reference and keep this manual up to date with any O&M changes.
The HTP Phoenix Gas Fired Water Heater (model PH119S) was installed in 2007 by Stephen Bohner of Alchemy Construction. This water heater is quite advanced, with the following characteristics:

The radiant floor system is also hands-off. When the annual or every-other-year inspection of the Phoenix is performed, the radiant system can also be checked for any issues.
Phoenix Installation Manual Phoenix User Manual Phoenix Warranty Information Taco Block Pump Manual

The Schuco Premium V Flat Plate Solar Collectors were installed by Ben Scurfield of Scurfield Solar in 2009. These collectors were chosen over more efficient evacuated tubes because they are high quality, low maintenance, and more durable than the evacuated tubes would have been. Some of the product characteristics include:
Click here to see the specifications for the Schuco Premium V Solar Collectors
The Phoenix is relatively hands-off. However, the most important consideration is keeping the area around the water heater clean and clear. Since it is a natural gas furnace, be sure not to keep anything combustible in the vicinity.
In addition, in order to ensure the Phoenix has a long life (and doesn't have to be resurrected from the ashes): Do not operate the appliance if its combustion air intake is located in or near one of the areas or in the vicinity of products listed in the following table. These areas will always contain hazardous contaminates that can form strong acids while passing through the burner and vent system. These acids will corrode the appliance's heat exchanger, burner components and vent system, resulting in flue gas spillage and/or water leakage, possible substantial property damage, severe personal injury, or death. If the appliance combustion air intake is located in any area likely to cause or contain contamination, or if products which would contaminate the air cannot be removed, the intake must be re-piped and terminated to another location.



PRODUCTS TO AVOID
Also, in order to adjust the temperature of stored water, press and hold {S3} for 2 seconds. The first item is: DU: Water Temperature Set Point – factory set at 119°F. Adjust down by pressing {S1} to a temperature as low as 95°F. Adjust up as high as 160°F by pressing the {S2}. Press {S3} again to display DH, the differential which is factory set at 7°F and adjustable down to 1°F by pressing {S1} and up to 18°F by pressing {S2}. Note: Due to the highly advanced control on this water heater, which compensates for varying inlet water temperature, the actual differential temperature may vary slightly from your setting. Press {S3} again to display the factory default temperature measurement in Fahrenheit. Change the default to Celsius by pressing {S1}. When finished, press {S3} one final time to place unit back into operation. The control automatically re-starts if no key is pressed for 2 minutes.
Finally, the radiant floors are controlled by the thermostat in the basement of CCAT. The thermostat is currently programmed to an occupied temperature and an unoccupied temperature. These temperatures, as well as the occupied and unoccupied settings, can be modified by reprogramming the thermostat.
The system is designed to require no operational attention and very little maintenance attention.
Check Temperature Display and Pressure Gauge (Monthly)
Check Pressure Relief Valve (Monthly)
Check Primary and Gas Piping (Every 6 Months)
Operate Pressure Relief Valve (Every 6 Months)
Check the pH of the propylene glycol/water mixture (Yearly) Check the pH of the propylene glycol/water mixture by taking a small sample of the fluid from the spigot at the base of the water heater tank. Only open the spigot a small amount as the contents are pressurized and potentially very hot! The pH of the propylene glycol/water mixture should be above pH 8 (should be around pH 10).
| Problem | Suggestion |
|---|---|
| HEATER ERROR |
|
| LOCKOUT |
|
The propylene glycol mixture prevents the system from freezing. In addition, the system was designed with steam-back protection to protect it from overheating. If the pump were to break down, the system is designed so that the amount of propylene glycol that would vaporize would fill the expansion tank without causing damage to the system. If you have any concerns that the pump is not working, or if you think there is a leak, call a professional immediately to inspect the system. Do not attempt to fix it yourself, as the contents may be highly pressurized and very hot!
Do not be alarmed by the fact that the Oventrop DeltaSol BS controller for the pump is not connected to anything. The Oventrop controller was replaced by the SunEarth controller and datalogger (see below), but it was left in place in order to preserve aesthetics and because it would otherwise leave a large hole in the insulation.
Overall, neither the Phoenix Water Heater nor the radiant floors should require much attention. The most important thing is to keep that basement room clear of hazardous materials and clean. It will also be important to establish a regular maintenance schedule with Alchemy Construction with a reliable place to record when maintenance occurred.
The solar thermal collectors were designed to not require much attention. Figure out a reliable way to keep track of the long-term maintenance tasks.
| Authors | BethEschenbach, Adam2290, Torincleats, Parafox |
|---|---|
| License | CC-BY-SA-3.0 |
| Organizations | Cal Poly Humboldt, Campus Center for Appropriate Technology (CCAT) |
| Derivative of | HEIF CCAT solar hot water system |
| Cite as | Nickturmanbryant, Jmc1238 (2014–2026). "Humboldt Energy Independence Fund/CCAT solar hot water system/Operation and maintenance". Appropedia. Retrieved September 28, 2026. |