When you turn your hot water tap on, you expect hot water to flow out. Whether it is a shower, bath, kitchen sink or laundry basin, water at a particular temperature will always run from the faucets in your home or workplaces. But how does that occur?

A tempering valve has a temperature sensitive element which focuses on adjusting the mix of hot/cold water depending on two factors:

According to National Plumbing and Drainage Standard AS/NZS 3500.4: 2003, some water installations are not permitted to deliver water at a temperature higher than 50℃/45℃, which is why a TMV is installed – to assist with temperature regulation.

https://www.business.qld.gov.au/industries/building-property-development/building-construction/laws-codes-standards/sustainable-housing

1. I took off the screws of the back of my OTA (I know I shouldn't have!) and now I'm not sure how to put them back on (see attachments). When I try it seems to push the primary mirror instead of fastening to anything.

4. My secondary baffle is sliding off. I've read that this is a problem w/older models. I tried pushing it to the right place and it requires some force, but after 1 minute it slides back to its original place. What should I do? Does this matter?

You are so kind. Thank you. I don’t know if I understand all the lingo. I just don’t understand why they won’t screw in, 3 of the inner ones will but others just seem to just push the back of the ota forward rather than screw into it.  Oops I ended up merging 2 and 3 but forgot to fix the numbering.

Can you submit an image of the flip mirror assembly? - as I think your second image is the mirror itself! - what did you clean it with?

Tempering valves and TMVs are the devices responsible for ensuring that the water that comes out of your tap is safe and at the right temperature. But, what is the difference?

I had a local engineering workshop make the replacement aluminium backplate. When fitted for the first time, it did not require collimating or other adjustments. Over the years since the 're-mod' my ETX105 has had one clean, collimated and service by SCTelescopes.

I think another SGL'er had a similar issue with his/her Maksutov or SCT secondary and removed and cleaned it up, then re-stuck it in position with a very thin layer of adhesive after a few 'dry' runs. I am not sure what adhesive he/she used, but if you decide to re-stick the secondary, I would...

You are so kind. Thank you. I don’t know if I understand all the lingo. I just don’t understand why they won’t screw in, 3 of the inner ones will but others just seem to just push the back of the ota forward rather than screw into it.  Oops I ended up merging 2 and 3 but forgot to fix the numbering.

I guess at this point if that baffle is off I wonder if it’s better to just try and buy a new scope. So much work for this one and I don’t even know if it’ll even work 🤨

An extremely useful website for all things ETX related is... http://www.weasner.com/etx/menu.html ...and for repairs, maintenance, tune-ups, etc., I would recommend... http://sctelescopes.com/  ...assuming you are living/residing in GB/UK 🇬🇧

Our plumbers provide professional maintenance and plumbing services – 24 hours a day, 7 days a week everywhere in Brisbane. If you have an emergency plumbing situation, then contact us now and we will come to you ASAP.

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2. My secondary mirror flip is broken, the plastic piece part fell off. Is it possible to fix? The mirror itself is also very dirty (see attachments) and I don't think it can be cleaned further. Any tips on how to replace it and where to buy the parts? Or is it possible to not use the 90 eye piece viewport and instead use the front one so I don't need to fix the flip or the mirror?

I have an old telescope, what appears to be a Meade ETX 90 from the early 2000s. I cleaned it pretty well after many Youtube videos and online research. I found full blown spider webs and dead spiders!

According to Queensland legislation, hot water is to be heated to a minimum of 60°C to prevent the growth of bacteria such as Legionella. A tempering valve ensures that hot water flows from taps at a maximum temperature of 50°C.

The mixing valve is a sliding component that is found in the tempering valve, ensuring the correct ratio of hot to cold water is being allowed to flow through. A tempering valve usually controls the temperature within ±3%.

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I guess at this point if that baffle is off I wonder if it’s better to just try and buy a new scope. So much work for this one and I don’t even know if it’ll even work 🤨

My ETX flip-mirror assembly got damaged, along with two of the three mounting points and a long crack in the ABS plastic cell after the OTA fell from one of my mounts when the cast-metal dovetail mounting snapped. (fortunately or luckily it was on grass/lawn). I have kept the mirror as it may come in use; (though I may sell it as I no longer have a use for it), and is in a VGC and clean condition and kept in a dust free bag in a drawer.

5. The plastic attachment to hold the smaller lens (finderscope?) wobbles no matter how tightly I screw it on. I don't know if it has anything to do with the front plastic part being a little broken.

I am excited to join this big star gazing community! I realize I am abusing of your kindness, so that you in advance for any help you can give.

Thermostatic mixing valves are required by law in the following locations, due to the possibility of high risk people being present (such as the elderly, sick or children):

A TMV mixes both hot and cold water together so it is a particular temperature (within 1℃ +/-) so it can be sent to different water outlets. The temperature is generally prearranged by a tradesperson or a qualified plumber, and the TMV element that responds to thermal activity alters the levels of hot and/or cold water to ensure the correct temperature.

Although TMVs and tempering valves get regularly mixed up, they are actually two separate devices. They both mix hot and cold water together to achieve a specific water temperature, but there are a few notable differences:

The jubilee/hose rings hold the OTA to the dovetail bar as I cannot find compatible diameter tube rings... "Vorsprung durch non-Technik".

2. My secondary mirror flip is broken, the plastic piece part fell off. Is it possible to fix? The mirror itself is also very dirty (see attachments) and I don't think it can be cleaned further. Any tips on how to replace it and where to buy the parts? Or is it possible to not use the 90 eye piece viewport and instead use the front one so I don't need to fix the flip or the mirror?

A thermostatic mixing valve, which is also known as a TMV, is a tool that combines hot and cold water together to maintain a specific water temperature when sending water through a faucet.

https://www.health.qld.gov.au/public-health/industry-environment/environment-land-water/water/risk-management/plan/implement/monitoring-temperature

A tempering valve, which is also known as a hot water mixing valve or a hot water tempering valve, is either a 2-inlet or 3-inlet mixing valve which is adjustable and activated by temperature. It mixes both hot and cold water together to achieve a desired temperature, in order to regulate the temperature of hot water that flows from outlets in your home.