Thermostat Fault Checks
Thermostat Not Working or Not Connecting to the Boiler: Safe Checks
If your thermostat is not connecting to the boiler, check its batteries, heating settings and connection status, then follow the instructions for your exact model. For London households, All Service 4 U can assess faults that persist after safe checks. Smell gas: leave and call the National Gas Emergency Service on 0800 111 999.
App problems, lost receiver connections and boiler faults need different checks. Start below, or read smart thermostats and heating controls explained for background.
Call with your postcode, the boiler make and any fault code showing.
- Gas Safe registered: 648977
- Phone line open 24/7
- Same-day appointments available
Before Checking Controls: Gas, Carbon Monoxide and Electrical Safety
Stop troubleshooting if you smell gas, hear a carbon monoxide alarm or suspect carbon monoxide exposure.
Gas smell
avoid flames and electrical switches. Open doors and windows and turn off gas at the meter only if safe. Leave and call 0800 111 999 from a safe place before booking a repair.
Carbon monoxide
treat an alarm as real; carbon monoxide has no smell. Get into fresh air. For suspected symptoms, seek help from NHS 111, or call 999 if serious. Contact 0800 111 999 without delaying medical care.
Safe user checks
use settings, accessible displays and manufacturer-approved battery compartments only. Never open boiler or receiver casings, touch terminals, bridge wires, bypass controls or work on gas. Stop if equipment is visibly damaged.
What Is Not Responding: App, Thermostat, Receiver or Boiler?
Identify the unresponsive device before trying to reconnect anything. App and hub connectivity can behave differently from local thermostat and receiver control; the arrangement depends on your system.
Blank thermostat display
this does not prove a boiler fault. Check user-replaceable batteries as the manual directs. Stop if the display stays blank or access would expose wiring.
App unavailable, local thermostat responds
this suggests an app-side problem, but does not identify its cause. Check Hive’s service-status and app-support information before changing pairing.
Thermostat reports lost connection
record the exact message and visible receiver lights. It does not prove the receiver has failed. Follow the matching reconnection guide; stop if unsuccessful.
Heating request shown, boiler idle
a displayed request does not prove the boiler received it. Check settings and note any boiler message. Persistent non-response needs diagnosis.
Boiler running, one radiator cold
connection failure is not established. Check that radiator’s target setting; report continued coldness without dismantling its valve.
Heating and hot water unavailable
this does not isolate the thermostat as the cause. Follow the no heating or no hot water checks and seek help if permitted checks do not restore operation.
Boiler Not Turning On With the Thermostat: Check the Heat Request
If the boiler is not turning on with the thermostat, first check whether the thermostat is requesting heating.
Compare temperatures
check the displayed room temperature against your chosen target.
Check heating mode
look for an off or holiday setting that could prevent heating.
Check timing
inspect the clock, schedule and any separate programmer.
Check batteries
replace them only where the user manual permits, using its specified type and orientation.
Request heat
use the ordinary user control, following the manual. Observe the thermostat, accessible receiver indicators and boiler display, then restore your preferred settings.
Record what changed and any complete message. Interpret symbols and normal operating delays using the exact control and boiler manuals, not another model’s instructions.
Hive Thermostat Not Connecting: Follow the Correct Reconnection Route
A Hive thermostat that is not connecting needs checks matched to its generation and the connection that has been lost.
Choose the matching symptom
distinguish a blank display, local connection warning and app-only failure. Hive’s Heating Offline and No Signal guidance address different observations.
Complete permitted checks
follow battery and placement guidance for your model. Use Hive’s applicable reconnection instructions, including app-led pairing only when specified.
Understand the action
restarting, re-pairing and factory resetting are different. A factory reset may remove configuration or associations; check the exact consequences and recovery steps before proceeding.
Check the outcome
test local heating response and app status separately.
Identify the thermostat, receiver and any Hive Hub from accessible labels or account information. Record the screen text and receiver light pattern without removing covers.
If a reset has already left the thermostat searching, record that history. Do not keep deleting devices or repeating resets when the correct procedure fails.
Hive Radiator Valve Not Working: Separate Connection From Heat Demand
A Hive radiator valve may have a connection problem or may not be requesting boiler heat. Successful pairing alone does not establish correct mechanical operation. Choose the branch matching what you observe.
Hive Radiator Valve Not Pairing: Check the Device and App Setup
If a Hive radiator valve is not pairing, check its batteries and reported connection status before following its model’s setup instructions.
- Identify the valve and distinguish an existing offline device from a new addition.
- Check the specified batteries and polarity through approved battery access.
- Record the valve message and the hub’s reported status.
- Follow the matching Hive add-device or reconnection route.
Record a failed attempt rather than repeatedly removing devices from the account. Do not remove the valve body or manipulate its pin.
Hive Radiator Valve Not Turning Heating On: Check Heat On Demand
A connected Hive radiator valve may not start heating if Heat On Demand is disabled or its operating conditions are unmet. Controlling radiator flow and requesting boiler heat are separate functions.
Using Hive’s Heat On Demand guidance for your equipment, check the thermostat association, feature setting, room target and heating mode. If the boiler is already heating but this radiator stays cold, report that observation for radiator diagnosis rather than continuing to re-pair it.
Nest, SALUS and Wiser: Use Instructions for Your Exact Control
Nest, SALUS and Wiser controls need their own model-specific connection and reset instructions. Identify the thermostat and matching receiver or hub first; similar-looking devices may use different procedures.
Nest Thermostat Not Connecting to Heat Link
If your Nest thermostat is not connecting to Heat Link, identify its generation and record the complete message. Use Google Nest Help’s matching UK Heat Link troubleshooting and indicator guidance.
Observe external indicators only. A Heat Link communication problem is distinct from app or Wi-Fi access. Check the consequences before choosing restart or factory reset. Use manual heating operation only where your exact user guide permits it, and stop if reconnection fails.
SALUS Thermostat Not Connecting to the Boiler
If a SALUS thermostat is not connecting to the boiler, match both thermostat and receiver model numbers before pairing.
Check the display, user-replaceable batteries, heating mode and accessible receiver indication. Follow the matching SALUS user manual for pairing and response checks. Instructions for an RT520RF apply to that model and its specified receiver, not every SALUS control. Do not open enclosures or borrow switch settings from another model.
Resetting a Wiser Room Thermostat: Check Reconnection First
Before resetting a Wiser room thermostat, check whether Drayton’s matching reconnection procedure can restore communication. Identify the room thermostat and HubR generation.
A battery restart, reconnection and factory reset are different actions. Check whether the proposed procedure removes the device’s system binding and requires adding it again. Record existing settings before an instructed reset and follow the matching recovery route. Do not substitute Wiser radiator-thermostat instructions or enter installer settings.
When to Stop Checking and Call a Heating Engineer
Call a heating engineer when permitted checks fail, the fault returns or the next step involves wiring or the boiler casing.
Stop for:
- Persistent loss of response or repeated disconnection.
- Visible equipment damage.
- A continuing boiler fault.
- Instructions requiring electrical testing or internal access.
Arrange heating controls and thermostat repair for professional diagnosis. An app message alone cannot establish which component failed.
Prepare the model names, full messages, light patterns, changes before failure and checks attempted. Include whether local heating still responds. Gas work requires appropriately qualified Gas Safe registered engineers; electrical controls work also needs appropriate competence.
Boiler repair, servicing and gas work
Get Help With a Thermostat Fault in London
For a thermostat fault that persists after safe checks, contact All Service 4 U to arrange an assessment in London. Our Gas Safe registered engineers cover domestic gas boilers and heating controls; our business registration is 648977.
Have your postcode, boiler and control models, symptoms and checks ready. Call us 24 hours a day, 7 days a week.
Discuss Your Thermostat Fault: 020 3740 6785, or contact us about a thermostat fault.
020 3740 6785
Frequently Asked Questions
Which Boilers Are Not Compatible With Hive?
Hive compatibility cannot be confirmed from the boiler brand alone. Check Hive’s Thermostat Boiler Compatibility Guide alongside the exact boiler manual. Technical compatibility and exclusions from a manufacturer’s installation service are different. Identify:
- The boiler model and control interface.
- The existing controls.
- The proposed Hive thermostat and receiver variant.
Have unresolved compatibility questions assessed before buying replacement controls.
Why Does My Hive Keep Disconnecting After It Reconnects?
Repeated disconnections need the affected connection and circumstances checked; the symptom alone does not establish a cause. Record whether local heating or only the app fails, battery condition, equipment moves, power interruptions and whether failure recurs in one location. Use Hive’s matching troubleshooting guidance with that record. Persistent recurrence needs diagnosis rather than repeated factory resets.
Can the Hive App Stop Working While the Thermostat Still Works?
Yes, app access and local heating control can behave differently. Check whether the thermostat still changes the heating before altering pairing. Record the local response and app message separately, then consult Hive’s service-status and app-support information. An app-only failure does not establish a broken boiler, and available offline functions depend on the installed model.
Should I Reset a Hive Radiator Valve Before Pairing It Again?
Reset it only when its model-specific troubleshooting instructions require it and you understand how to restore operation afterwards. Restarting, re-pairing and factory resetting are different actions. Check the matching Hive guide for effects on associations and configuration, and any required re-addition or calibration. Do not reset every valve as a blanket fix.
How Do I Check the Engineer Is Qualified to Work on My Gas Boiler?
Check the engineer’s current Gas Safe ID card for identity, validity and qualifications covering the required gas appliance work, and verify these through Gas Safe Register. Business registration does not replace checking the individual’s scope. User settings and ordinary wet radiator work do not automatically require Gas Safe registration, which also does not establish electrical competence.
Still have a question or need urgent assistance? Call 020 3740 6785, tell us what has happened and we will tell you what happens next.