In Anchorage, Eagle River, and the Mat-Su Valley, a huge percentage of homes do not have a standalone gas chimney water heater. Instead, they use an indirect storage tank—most commonly a blue or gray Amtrol Boilermate, Burnham Alliance, or SuperStor—heated by a dedicated zone off the main hydronic boiler.
Understanding how your boiler and indirect tank communicate explains two very common Alaska emergencies: (1) losing both heat and hot water simultaneously, or (2) having hot showers while the rest of your house freezes.
What To Do Right Now While Waiting for Dispatch
Step 1: Scenario A — Neither Showers Nor Baseboards Have Heat
If both domestic hot water and room heat are cold, the main boiler itself is locked out (power, igniter, gas valve, or pressure switch). Check the boiler first.
Step 2: Scenario B — Showers Are Hot, But House Baseboards Are Freezing
Look at your multi-zone relay box (Taco or Honeywell) on the wall. If the 'Priority Zone' light for the water heater has been glowing nonstop for over an hour, your boiler is stuck trying to heat the water tank and refusing to send heat to your rooms!
Step 3: Temporary Workaround — Turn Off 'Priority' Switch on the Relay Box
Many Taco SR503/SR504/SR506 zone control boxes have a small internal or external toggle switch labeled 'PRIORITY ON/OFF'. Turning Priority OFF allows your house heating zones to run simultaneously while our technician is en route.
Step 4: Call (907) 250-9156 for Boilermate & Zone Relay Service
Whether your Boilermate thermistor sensor failed, its heat-exchanger coil scaled up, or its zone valve stuck, our 24/7 crew can restore both heat and hot water fast.
Boiler + Indirect Water Heater Failure Scenarios
Diagnostic symptoms, mechanical fixes, and typical 2026 Anchorage / Mat-Su repair ranges:
| Component / Issue | What You Observe | Professional Alaska Fix | Typical Range |
|---|---|---|---|
| Boilermate Stuck in 'Priority Mode' Lockout | Showers are hot, boiler runs constantly, but zero heat goes to house baseboards. | Replace failed Boilermate digital control / thermistor probe or descale internal heat coil. | $325 – $695 |
| Failed Indirect Tank Zone Valve or Circulator | House baseboards are warm, but showers run ice cold. | Replace indirect zone circulator pump or Honeywell zone valve actuator. | $350 – $780 |
| Ruptured Internal Heat Exchanger Coil | Boiler pressure spikes to 30 PSI and relief valve dumps water continuously. | Domestic 60 PSI water is leaking into the 15 PSI boiler loop through a pinhole in the coil; replace indirect tank. | $2,200 – $4,500 |
How a Pinhole Inside an Indirect Water Heater Floods Your Boiler Room
Inside an Amtrol Boilermate or indirect tank, 60 PSI city/well drinking water surrounds a coil carrying 15 PSI boiler water. When an older internal coil develops a pinhole leak, high-pressure domestic water forces its way into the boiler loop—pegging the boiler gauge past 30 PSI and blowing water out the boiler relief valve nonstop.
Questions & Answers — Guide #9 · Indirect Water Heaters & Priority Zones
Direct answers from our licensed Alaska heating & plumbing crew.
Most Alaska hydronic systems wire the indirect water heater to 'Zone Priority' so the boiler dedicates 100% of its BTU output to reheating the water tank for 15–30 minutes. However, if the tank sensor fails or scale blocks heat transfer, the boiler never exits Priority Mode—leaving your house without heat.