Heat Pump Not Heating in Winter: Walking the Fault From Reversing Valve to Defrost in the Field
It's 28F outside, the homeowner says the air coming out feels lukewarm, and the outdoor unit is buried in frost. A no-heat heat pump call in winter has half a dozen plausible causes that all feel the same at the thermostat. R-Pro's field app walks you from symptom to cause to repair steps against 600+ real cases right there in the driveway, and when the part list firms up, the office ERP turns it into a quote, an invoice, and a clean accounting entry without you typing it twice.
On Site: Walk the Fault From Reversing Valve to Defrost
- Start at the indoor air temp: lukewarm supply with the system calling for heat usually points to the reversing valve stuck in cooling or a weak solenoid, not a refrigerant problem — feel the discharge and suction lines at the outdoor unit to confirm which mode it's actually running.
- Pull the panel and check the defrost board: a heat pump iced solid in winter often means the defrost cycle never initiated — verify the defrost thermostat (coil sensor) closes, the timer/board advances, and the reversing valve energizes during defrost.
- Type the symptom into R-Pro's AI diagnosis — 'heat pump not heating, outdoor coil frosted, lukewarm supply air' — and it matches against 600+ real HVAC and refrigeration cases, returning ranked causes (stuck reversing valve, failed defrost sensor, low charge, open run capacitor, control board) with the field check for each.
- Scan the outdoor unit nameplate with your phone to auto-fill model, serial, refrigerant type and charge — no squinting at a frosted label or hand-copying it into your notes.
- Drop a voice memo while your hands are cold: 'reversing valve solenoid not clicking on heat call, defrost sensor reads open at 31F' — it attaches straight to this customer's history so the next visit starts where this one ended.
Back at the Office: Quote, Invoice and Book the Repair
- Build the quote in the ERP from the confirmed parts — reversing valve solenoid coil, defrost board, defrost thermostat, capacitor — with labor lines, and send an itemized estimate the homeowner can approve before you order anything.
- Issue the invoice and a proper tax invoice with YOUR country's tax set the way you run it — VAT, GST or sales tax, your own name and rate — not a hard-coded format that doesn't match your jurisdiction.
- Track the reversing valve and defrost board through inventory and purchase orders so you know what's on the truck, what's on order from which supplier, and what the part actually cost you.
- Post the job to accounting automatically: sales, the parts purchase, expenses and net profit all land in the books, and the customer ledger shows this winter call against everything you've done at that address.
- Pull reports at month-end to see how many no-heat heat pump calls came in, your real margin on reversing valve jobs, and which suppliers are pricing defrost boards competitively.
The Connection: One Diagnosis, No Double Entry
- The nameplate you scanned, the parts you confirmed, and the voice memo from the driveway flow from the field app into the office ERP — the quote practically writes itself from what you already captured on site.
- Because field work feeds the office books automatically, you're not re-keying the model number, the parts, or the labor hours into a separate accounting program after dark.
- Everything works fully offline in the field — frosted-over crawlspace, rural property with no signal — and syncs to the ERP the moment you're back in range, so a dead zone never costs you a record.
- The per-customer service history means the next time that heat pump throws a defrost fault, you already know the valve was replaced last January and which board went in — diagnosis on the return visit starts ahead.
- Both tools run in 10 languages under one subscription, so the field diagnosis and the office accounting speak the same language as your crew and your customers.
Diagnose it in the driveway, bill it from the office
R-Pro is two strong tools working together: a field app that walks a no-heat heat pump from reversing valve to defrost against 600+ real cases, scans nameplates, and works fully offline — and an office ERP that turns the confirmed repair into quotes, tax invoices, inventory and accounting. One subscription, 10 languages, and your winter field calls flow into the books with no double entry.
Get R-Pro →FAQ
How do I tell if it's the reversing valve or just the defrost cycle?
Feel the line temperatures at the outdoor unit on a heat call: if the system is moving heat outdoors instead of indoors, the reversing valve is likely stuck or its solenoid isn't energizing. If the coil is frosted solid and the unit never reverses to clear it, suspect the defrost board, the defrost (coil) thermostat, or the timer not initiating. R-Pro's AI diagnosis ranks these against real cases from the exact symptoms you enter, with the field check for each so you confirm before you condemn a part.
Can R-Pro diagnose the no-heat call with no signal at the property?
Yes. The field app's case-based AI diagnosis, nameplate scanning, voice memos, customer history and on-site receipts all work fully offline. You diagnose and document the heat pump in a basement or rural property with zero bars, and it syncs to the office ERP automatically once you're back in coverage.
Does the reversing valve and defrost board I quote tie back to my accounting?
It does. When you build the quote in the ERP and it becomes an invoice, the sale, the parts purchase from your supplier, and the expenses post straight into accounting and the customer ledger — sales, purchases, net profit and inventory all update without separate data entry.
Can I set the tax to match my own country on the invoice?
Yes. The office ERP lets you set your own tax name and rate — VAT, GST or sales tax — so the tax invoice you hand the homeowner for the heat pump repair matches how you're actually registered, not a fixed template built for somewhere else.