Relay 90-293q re-wiring question

Is this the boiler wiring or the thermostat /zone valve wiring or both ? There is a wiring diagram on the inside of the cover ?

Color changes and wire gauge may be intentional and do not need to be remedied, hard to say from here. If in doubt use the heaver gauge if you want wire gauge consistency.

If there is no wiring diagram for a troubleshooting reference they all could be black wires, however color helps to trace things out if needed.

Crimping tools, that is, the actual manufactures recommendation are usually product specific. You would have to look at the data sheet for the product you are going to use. In your picture I already see two different styles of connector. So it appears someone was there before making a mess of things, but it probably worked well beyond the warranty period so no one usually cares much. Finding manufacturing quality crimps in field wired equipment is very rare.

Well if you are relocating things the wires will be longer.

Folks usually make a mess out of wiring and leave to the next gut to figure out.

14 Ga. is fine, probably overkill unless you are powering a circulator through that wire. No, not talking down to you, although I think you don't understand the vastness of what you are asking. This is just one example;

Let me put it this way, I don't like crimps, they fail way too often and sometimes it is hard to find the failed connection. Most folks use the inexpensive 'Kit' from the big box store or their favorite electrical supplier and it gets the job done. I've seen crimps that look good to the eye and feel secure that are a total failure under load when viewed with a IR thermal camera.

The industry uses crimps since they are quick, inexpensive, generally last beyond the products warranty period and over thousands or millions of crimps the cost of the tooling is almost nothing. Some tools are over $100 and don't include the dies.

For myself (when forced to use that type of wire termination) I often use un-insulated or I remove the insulation from an insulated crimp on connector, crimp it with a generic crimping tool and then solder it, once it cools a bit I remove the flux and put a layer or two of heat shrink tubing to strain relief it and it also helps seal it. Usually the heat shrink tubing is slid over the wire before the termination is crimped on. For automotive or harsh environments I use the heat shrink tubing with the intermelt (hot melt adhesive). I've had zero issues with this method, however it is more time consuming, need to be able to solder and have heat shrink tubing.

Also I find it awkward and/or maybe just silly to recommend an expensive tool that may do an exceptional job when used correctly for a dozen wire terminations.

At work they have so many crimping tools it is often hard to find a suitable one. And I am not the guy that buys them so I rarely look at the make and model, just look at the die to see if it matches the terminal I am trying to crimp. If I don't like the crimp I get, it gets cut off and redone and/or redone with a different tool or just soldered depending on the application / situation.

The proper way is to decide on the wire termination you want that suits your needs / application, look up its data sheet and procure the manufacture's recommended crimping tool for that wire termination. I would venture to say that never happens for wiring repair in the field in the HVAC industry. Maybe it does in the aviation industry, I don't know.

However there nothing saying you can't go above and beyond the typical field wiring repair quality. For me crimp, solder, heat shrink, some folks won't like that method for various reasons.

I started using wire ferrules on stranded wire after visiting a few control manufacturers in Germany, years ago. They are used on control and line voltage wiring.

The crimper I bought squeezes 6 sides and does not release until it is closed all the way, so no issues with under-crimping.

I believe DIN certified ferrules are required to get CE certification on wired components.

I also learned wire gauge in Europe are metric sized so you may notice European wiring terminal strips don't always accept AWG wire size without some wrestling , especially stranded control wire.

So the ferrules help when working with Euro based control, most mod cons wiring in general. They look professional also.

Basic kits from ferrulesdirect.com

Ferrules are quick and easy and you can color code the various wires with your ferrule selection.

Not many plumbers carry soldering irons or pencils :) Tinning wires with a torch takes some practice.

The white ones in the assortment allow you to write on them

It's nice to know that some of us are still doing "Rocker Surgery" on the HVAC systems in out homes. And I like to use tiny wire nuts with different gauge wire twisted together after twisting them the wrong way because I'm left handed. Now that is what I call "Perfect"

There is a story that goes with "Perfect". Read this one:

@tonynap I'm not the only one that promotes the use of a meter here. It often just makes troubleshooting so much easier. Parts cannon can work, often it is expensive and time consuming and may not repair the issue. Many folks don't know how to use a meter or are afraid of electricity. Yeah never know. If a meter can be used it is usually a benefit.

27 VAC is fine, 24 VAC is a nominal voltage. If you have a 40 VA transformer that is not loaded to 40 VA (fully loaded) the transformer's output voltage is more often than not higher than nominal.