System Won't Heat
Chromagen Solar Water Heater
Severity: ModerateWhat Does This Error Mean?
If the controller shows no error but the water stays cold on a sunny day, the pump is the most likely culprit — it has stopped circulating fluid between the panels and the tank. Check the controller display, verify boost is enabled, and feel whether the pipes near the pump are warm.
Affected Models
- Chromagen CR Series
- Chromagen Optima
- Chromagen Crown
- Chromagen Prisma
Common Causes
- Circulation pump not running (pump failure or power issue)
- Airlock preventing water flow despite pump running
- Drain-back valve stuck closed
- Sensor drift — controller thinks the tank is already hot
- Frost damage to pipes blocking flow
- Scale buildup in collector reducing efficiency over time
How to Fix It
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Confirm it is a genuinely sunny day.
The system needs direct sun — the collector must be at least 8–10°C hotter than the tank before the pump activates. On partly cloudy days, short pump cycles may not heat the tank noticeably.
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Check the collector temperature on the controller.
Many Chromagen controllers show the temperature difference between the collector (T2) and tank (T1). If T2 is much higher than T1 but the pump is not running, the pump has failed.
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Listen for the pump.
On a warm sunny day, put your ear near the circulation unit — you should hear a faint hum from the pump motor. No sound means no power to the pump or the pump itself has seized.
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Check the circuit breaker for the pump.
The solar pump usually has its own circuit breaker in the switchboard. If it has tripped, reset it. If it trips again immediately, there is a wiring or motor fault — call a technician.
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Flush for airlocks if the pump is running.
If the pump hums but pipes stay cold, an airlock is blocking flow. A technician can bleed the system and restore circulation.
When to Call a Professional
If the pump appears to run but no heating occurs, or if there are any leaks, a qualified solar technician is needed to diagnose the flow and pressure issues.
Frequently Asked Questions
The controller shows the collector is 60°C but the tank is still cold — why?
If the collector is hot but the tank is not heating, the pump is not circulating water between them. The pump motor, wiring, or a seized impeller is the most likely cause.
The system worked fine for years — why would the pump fail now?
Solar circulation pumps typically last 10–15 years. Gradual scale buildup and bearing wear eventually cause them to seize or run too slowly to circulate effectively.