Potterton E87 Fault Code: Causes, Fixes & Repair Costs
What does the Potterton E87 fault code mean?
The E87 fault code on a Potterton boiler indicates that the boiler has lost communication with the room controller or thermostat. In plain terms, the boiler cannot 'hear' the device that is supposed to tell it when to fire up. This is part of a family of related communication fault codes — E83, E84, E85, E86, and E87 — all of which point to a breakdown in the link between the room controller and the boiler. While the specific sub-code displayed can hint at whether the issue is with pairing, signal quality, or the controller itself, the root cause category is the same across all five. Importantly, E87 is not a gas-safety fault; it will not put your household at risk from gas or carbon monoxide. However, it will typically prevent your heating and hot water from working normally until the communication link is restored.
General guidance only — not a substitute for professional advice, and not certified by a Gas Safe engineer. Always have your specific appliance assessed by a qualified professional. Any gas work must be carried out by a Gas Safe registered engineer. If you smell gas or suspect carbon monoxide, leave the property and call the National Gas Emergency line on 0800 111 999.
Common causes
- Thermostat not paired or has lost pairing with the boiler Common
The most common trigger for E83–E87 codes. Wireless and RF thermostats occasionally lose their pairing with the boiler receiver, particularly after a power cut or battery change. The boiler then reports a communication failure because it receives no signal at all. Re-pairing via the thermostat's own pairing mode (as described in its manual) often clears this instantly.
- Faulty or incompatible room controller Common
If the thermostat or timer has developed an internal fault, it will either send corrupt data or stop transmitting altogether. Similarly, a replacement thermostat that is not compatible with Potterton's communication protocol will never establish a valid link, showing E84–E87 on the boiler display.
- Loose or damaged wiring between the controller and boiler Sometimes
On wired installations, a loose terminal, a corroded connector, or a pinched cable can interrupt the communication signal. This is more likely in older installations or where recent decorating work has disturbed the wiring route.
- RF channel conflict or wireless interference Sometimes
Wireless thermostats transmit on a specific radio frequency channel. If a neighbouring property uses a compatible thermostat on the same channel, signals can clash or cancel each other out, causing intermittent or persistent communication faults. Changing the channel on both the receiver and the thermostat head usually resolves this.
- PCB fault Rare
The boiler's printed circuit board handles all incoming signals from external controllers. If the PCB is failing — often due to age, moisture ingress, or component wear — it may stop recognising the thermostat signal even when the thermostat itself is working correctly. PCB faults are less common than thermostat issues but should be considered when all other checks have been ruled out.
How to fix it
- Reset the boiler DIY safe
Locate the reset button on your Potterton boiler's control panel and hold it for approximately three to five seconds. If the E87 code returns quickly after resetting, do not keep repeating the reset more than two or three times in total — a persistent fault needs investigation rather than repeated resets.
- Check the room thermostat has power DIY safe
If you have a wireless thermostat, check that its batteries are not flat and replace them if needed. For a wired thermostat, confirm that power is reaching the unit. A thermostat with no power cannot send any signal to the boiler.
- Re-pair the thermostat with the boiler receiver DIY safe
Consult the pairing section of your thermostat's instruction manual. Most Potterton-compatible wireless thermostats have a dedicated pairing button or a menu option to re-establish the link with the boiler receiver. Follow the steps carefully — the receiver usually needs to be put into 'learn' mode at the same time. A successful re-pair will often clear the E87 fault immediately.
- Check and change the RF channel if neighbours use a similar thermostat DIY safe
If you suspect signal interference from a neighbouring property, your thermostat manual will explain how to change the radio channel. Both the thermostat head and the receiver unit must be set to the same new channel. Try at least two or three different channels and reset the boiler after each change to see if the fault clears.
- Visually inspect any accessible thermostat wiring DIY safe
On wired installations, switch off the boiler at the fused spur before touching any wiring. Check the terminals at the thermostat backplate and at the boiler connection point for obvious signs of looseness, corrosion, or damage. Gently re-seat any loose cables. Do not attempt to work on wiring inside the boiler casing — this must be done by a qualified engineer.
- Call a Gas Safe registered engineer if the fault persists Gas Safe engineer
If re-pairing, channel changes, and a boiler reset have not cleared the E87 code, the fault lies with components that need professional diagnosis — most likely the wiring inside the boiler, the receiver unit, or the PCB. A Gas Safe registered engineer will carry out a full electrical diagnostic, test the communication circuit, and replace whichever component is at fault. Do not attempt to open the boiler casing yourself.
Parts you may need
- Wireless thermostat and receiver kit (Potterton-compatible) · from £80
- Programmable room thermostat (wired) · from £45
- Boiler PCB (Potterton model-specific) · from £220
- Thermostat wiring harness / connection cable · from £15
The exact spare depends on your boiler's GC number (on the data badge). Check this against the part before buying.
Typical repair cost
Expect to pay roughly £100–£350, depending on the underlying cause.
Frequently asked questions
Is the Potterton E87 fault code dangerous?
No. Unlike fault codes that relate to gas pressure, flue gases, or ignition failures, E87 is purely an electrical communication error between the thermostat and the boiler. It poses no direct safety risk from gas or carbon monoxide. Your boiler will typically lock out or run in a limited mode until the communication link is restored, but you do not need to evacuate or isolate the gas supply.
What is the difference between E83, E84, E85, E86, and E87 on a Potterton boiler?
All five codes belong to the same communication fault family and indicate the boiler has lost contact with the room controller. The slight differences between them point to where in the communication process the breakdown is occurring — for example, E83 may suggest no signal is being received at all, while E85–E87 can indicate the signal is being received but is invalid or out of sync. In practice, the diagnosis and fix are very similar for all five: start with re-pairing the thermostat and checking the wiring before escalating to an engineer.
Can I fix the E87 fault myself without calling an engineer?
Quite possibly, yes. The most common cause is simply a lost pairing between a wireless thermostat and the boiler receiver, which you can fix yourself by following the re-pairing instructions in your thermostat's manual. Replacing flat batteries and changing the RF channel are also straightforward homeowner tasks. If these steps do not work, however, the fault is likely inside the boiler — wiring or the PCB — and you will need a Gas Safe registered engineer to investigate safely.
How much does it cost to fix a Potterton E87 fault code in the UK?
For the most common cause — a thermostat replacement or re-pairing job — you can expect to pay roughly £100–£350 including parts and an engineer's call-out. Wiring repairs tend to sit at the lower end of that range. If the PCB turns out to be the culprit, parts and labour can push the total to £450–£700 depending on your region and the specific board required; this is worth bearing in mind on older boilers where the overall value of further repairs should be weighed against the cost of a replacement boiler.