Navien combi asme boilers

I have an Opentherm capable boiler which runs at a fixed 70 degrees in “classic” S-plan (without opentherm controls)

• one “hot water” zone which actually needs the 70 degrees to heat an unvented cylinder
• one “heating” zone which is for underfloor heating and is immediately down-mixed to 40 degrees

This is wasteful, the boiler runs at much too high a flow temperature most of the time. It does not cycle badly because it can modulate down well to produce the right heat output, but it would be a lot more efficient if it ran at 40 degrees unless hot water is required.
The simplest way would be a tiny controller which asks the boiler to run at 40 degrees if only heating is demanded, or 70 degrees if water is demanded (alone or in combination with heating). Basically two inputs from the existing boiler stat and UFH system, and an opentherm output.
Moving to smart opentherm thermostats is not an really an option as the UFH system has 12 individual sub-zones, each with their own thermostat, and is not designed well enough to have a single constant flow temperature in any case. Also none seem to support S-plans, only combi boilers.
Is there anything on the market that simply commands two different flow temperatures depending on demand, or do I have to learn how to “roll my own” using an Arduino?

What is a rough price for replacing a boiler? Unit and fitting.
We have had many quotes varying in price.
Currently, we have a standard gas boiler with a water tank.
We would like to replace with a standard Combi boiler.
House is a 3 bedroom 1 bath 1 shower.
Any help or suggestions is appreciated👍.

Title basically says it, but I guess a side question is would any plumber actually go along with that? Combi boiler was professionally installed and they did a great job. Cleaning up the joists and running the pex seems like a ton of work, and not particularly skilled so I figure I could save some money and do all that grunt work myself? Seem reasonable?

Hello everyone! I wanted to share my personal journey on how I became a Second Class Fireman. It all started when a friend of a friend introduced me to the industry. I was intrigued, and he became my mentor, teaching me more about the field.
He lent me a copy of “Boiler Operator’s Exam, Preparation Guide” by Theodore B Sauselein (this can be found online), and we met up and practiced questions weekly. I also studied Quizlets, both my own and ones I found online.
We started meeting up in February and I began studying and taking notes. I took my written exam at the end of April in Stow. I passed and got a call and email later confirming my oral exam at the beginning of May. I took the oral exam and passed.
I have been searching for a job for almost two weeks now with no luck so far but I haven’t given up hope. I just need someone to give me a chance and get my foot in the door. I hope this helps everyone else reading this and feeling unmotivated. Remember, every journey begins with a single step. Keep pushing forward!
Here's some resources for those of you studying:
My written Quizlet
Questions from book Quizlet
ASME symbol Quizlet
Feel free to comment any questions :)

Every mixer tap i've had installed seems to slowly get worse over time and will eventually be just hot or cold and no in between, is this to do with the combi boiler getting older or something to do with the mixer that i could fix? Couldn't find anything at all on google about this.

Hello, new to this subreddit, but other subreddits have given me good advice so many times that thought it might be worth an ask!
Does anyone know what might be the cause of my current plumbing woes? Or can point me for a phrase to search to read more?
Context of house refurb: - Ex- council (solidly built)1950s semi detached house in UK, was basically untouched until recent refurb project. - Original copper water pipe from mains supply pipe in road to where in enters house in the kitchen. - All other pipes for water and heating inside house newly installed in last few months- modern width was my understanding. - I know from water company that although the pipes into the house are fairly narrow copper pipes that the pressure is good due to local geography. - my neighbours don't have upstairs/downstairs differences in water flow (at least by eye, haven't got them to measure yet)
Downstairs plumbing seems okay: - Outside tap seems good and works fine with pressure washer - Kitchen tap (direct to mains) takes 7 seconds to fill a one litre jug on cold only, 9 seconds on hot only. Not super high flow I know (something like 9 litres per minute on cold), but not noticeably slow. - there's a water softener unit that connects to everything that's inside apart from kitchen sink tap (as hard water area, was recommended. I'm new to using one). - there's a new combi gas boiler running hot water and central heating with standard radiators.
Upstairs bathroom has a much lower flow rate: - Shower on a medium setting takes 15 seconds to fill a one litre jug (4 litres per minute). Like using a watering can! - Bathroom tap on cold takes something like 15 seconds for one litre (4 litres a second). Takes about twice as long after toilet has been flushed.
Any idea what might be going on? Could it be related to the water softener? Or internal pipework going up 2m to the bathroom?
Builder in charge of refurb is supportive (plumber has made several other daft mistakes and has had to move pipes several times to include fitted appliances). But useful to know what else I could check or investigate before they come back later in the week.
Thanks in advance! Any clues appreciated!

Help - Nest Smart Thermostat Hub not Working after Electrician Installation
Hello. I had an electrician wire up two nest learning thermostats to my ideal logic 35 ESP1 Combi Boiler. He wired it and turned the thermostat on and the hubs lit up and connected, the thermostat works and me being an idiot just let him leave without actually seeing if the radiators worked. I’ve just tried heating it up the radiators and the hubs have power, the thermostats are connected to WiFi and my phone, but there seems to be an issue of communication between the thermostats and the boiler as the boiler is not receiving the heating instruction from the thermostats. My house is a two stage heating call to heat system (downstairs and upstairs) and both thermostats have this issue.
I’ve just taken off the faceplate and it’s spaghetti junction and of course as a DIYer I’m completely lost. Im thinking there must be wiring that is the wrong way round? Hoping someone can help as there’s a mixture of types of wires and I’m very confused.
If it’s a case of me turning power off at the box and simply switching cables around I’m more than capable of that and would be keen to get this working. If not and it’s a bigger issue I’ll get the spark back.
Thanks for your help!

We are renovating a house we just purchased, 4 bed south london. Thinking of adding solar to the roof (east west facing). However we will most likely be converting the loft in 3-4 years by adding a dormer. Is it really stupid to add solar to a roof we know we will have to remove in the future? Will this be quite costly? In terms of the dormer itself, can you add solar panels to a dormer or would we have to design the dormer with a sloped roof.
Finally is a conventual gas combi boiler still the way to go with solar panels or should we be looking at electric boilers?
Many thanks in advance.

The cylinder is set to heat water to 50 Celcius, then someone has a shower using say 20% of the hot water, then the cylinder fills with cold, then the remaining water in the cylinder is too cold for the next person to immediately have a shower. Do I just need to turn up the temperature on the cylinder, or just wait for it to reheat? Or am I missing something?

Looking to get a combi boiler installed, anyone have good or bad stories about Navien? It's £400 cheaper than a Worcester Bosch

I'm looking at getting a solar battery fitted in my garage which also houses the Combi boiler and both the gas and electric meters. The installer is saying they need a 1m separation between any gas appliance and the battery. Is there a Spec or Reg they are using from Gas or electric codes as both the meters are installed with 45cm of the boiler? I don't want to lose half my garage wall pace to a battery that's on 30cm wide.

I'm a bit in an awkward situation and i'm not sure if this is a rant or a proper cry for help.
Background: i live in a property (England) that is part of a block with 4 apartments. These used to be council flats but now between 8 of us we are the owners of the building and have freehold through a company. My flat is situated on 1st floor and the access to the loft if through my property.
Context: two weeks ago, I got a letter from the council stating they will send a team of contractors to clean the water tanks from the loft (which are not used anyway, as all flats connected to them, have combi boilers). Boys came last week on thursday, did the job of cleaning the tanks and left in a rush. On monday my ceiling and walls were damnp and had pockets of water in them, the loft tanks were leaking and my home soaking wet. Called the council afterhours team who said they will send an electrician to asess the electricals but they can't send a plumber as the water is just dripping and can be "contained". I accepted and been given a reference number. Nobody showed up.
Problem: apart from the soaking wet ceiling and walls, the the fire alarms triggered today only to find out that one of them was soaking wet. Called again the council to ask for help (as this is their doing) only to find out that "because we own the property they can't send anyone as the system won't allow to send contractors if we don't rent" - which is plain outrageous.
I mean, who is liable for all of this and what can be done in a situation like this? I'm baffled

Hello all.
I was looking at older posts but couldn't find the right answer so hoping someone can help.
My heating system is in need of a much required upgrade. My plumber has suggested we get a Valiant EcoTec Plus 635 System Boiler and Megaflo Eco 2 300i tank. My plumber is great and I trust this suggestion, although he is a bit old school and does not know about Smart Tech so need to make sure whatever Smart Tech system I get is compatible with this boiler and tank. Doing research it seems like this boiler and tank will be more than sufficient to heat the flat. Our current combi boiler can't handle any hot water tap and the shower running!
My place is a 3 bed flat with 7 radiators (1 kitchen, 1 living room, 2 hallway and 3 bedrooms). There is also a heated towel rail that won't need the smart tech.
The requirement is for smart valves with thermostats on each of the 7 radiators connected to an app. The app should have basic functionality like turning up/down the temperature for each individual radiator, setting schedules like on in the morning or a certain temperature. Also if there is advanced functionality like heating the megaflo tank in the morning ready for showers and off at night to save on energy costs and such would be great. My flat has good WiFi coverage so all the valves could connect via WiFi very easily.
A wireless thermostat on the wall connected to the boiler system and radiators incase my phone is in the other room and I walk past the thermostat wanting to change temperatures would be great also.
I have been looking into this and it looks like Drayton Wiser or Tado are the front runners. Or if there are any suggestions?
Looking for any options and the best way for this 🙂
Thanks so much.

Need to find out if what I’d like to do is even possible. I had originally spoken a rep from Navien who thought it was possible (pre-install) and now that it’s installed it’s not functioning as planned. We installed a Navien Combi in series behind a hpwh. The idea was to use the hpwh as primary, and if the tank temp fell far enough the Navien DHW would pick up the slack. Problem is Navien seems to fire and run on FLOW and not inlet temp. This caused the Navien to fire and run anytime hot water is called for, albeit running at basically 10% because theirs no heat needed. Anyone know if there’s a way to configure this so that doesn’t happen?