Most engineers are going to focus on the main PCB when they're trying to figure out what's gone wrong with their Rinnai HD70. And let's be fair, they probably should. But there's another bit of kit that's doing a pretty vital job in the background - the sub PCB. And when this one packs up, it's not at all hard to misread the symptoms and end up with a big headache.
The P70EV-701 is effectively a sub PCB and a surge protector all in one neat package. It's a pretty crucial dual role, and it's not complicated at all but it's bloody important. First off, it sorts out the electrical link to the solenoid valves - a secondary circuit board that's got to be working properly if you want to avoid problems. Then when the unit is shut down by a diagnostic code (ie, the main PCB has given up after detecting a fault), the sub PCB kicks in and keeps the solenoid valves ticking over - which means you still get freeze protection and solenoid operation even when the main board has given up the ghost. And if that sounds like a big deal, it is, especially with the bad weather we get in the UK in the winter - an external water heater is just begging to freeze solid overnight.
The second reason this bit of kit is so important is that it protects the appliance's main electronics from those nasty voltage spikes that come in on the mains supply. Whether those spikes come from the grid, or from nearby lightning, they can easily blow the main PCB to bits in an instant - leaving you with a nice big repair bill. The sub PCB absorbs and suppresses those spikes before they get anywhere near the main board. And if this component fails or gets damaged while you're messing about with the appliance, you'll need to swap it out with the correct genuine part. This is it.
The sub PCB is the first line of defence between your mains supply and your solenoid circuit. It takes all the muck that the mains can throw at it - and when it's all working correctly the main PCB never has to lift a finger. Fit some dodgy alternative in this position and you're relying on some pretty untested components to protect expensive electronics and critical freeze protection systems. The manuals for those solenoid valves that connect to the main sub PCB all make it pretty clear: you'll need a surge protector with some decent terminals & that's exactly what the P70EV-701 is. Its a genuine part that's specified for the HD70 series & its been built to the same high standards as every other bit of this appliance. Its a breeze to integrate into your existing wiring & it does its two jobs - keeping your system free from surges and making sure the solenoid valve stays active - without any hiccups. Do yourself a favour & don't leave that main PCB exposed to the elements, get the right part in place.
If you order before 3pm, we'll get your new bit posted out asap. You can have your genuine Rinnai HD70 sub PCB and surge protector on its way to you today.
Got a HD70 model that you want to check is compatible with this part - no worries, just give us a shout - we'll check it for you before you place your order.
| Brand | Rinnai |
|---|---|
| Part Number | P70EV-701 |
| Product Type | Sub PCB / Surge Protector |
| Compatible Series | Rinnai HD70 Series (REU-VRM3237 / REU-VR3237) |
| Primary Function | Solenoid valve circuit continuity during PCB fault conditions |
| Secondary Function | Mains surge and voltage spike protection for main PCB |
| Appliance Type | Continuous Flow Gas Water Heater |
| Part Type | Genuine OEM Replacement |
| Installation | Gas Safe registered engineer required |
